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COPYRIGHT 1898 BY THE OPEN COURT PUBLISHING CO. 



THOMAS HOBBES 

1 588-1679 
After a portrait by Dobson in the possession of the Royal Society 



THE 

Metaphysical System of Hobbes 



AS CONTAINED IN TWELVE CHAPTERS 
FROM HIS "ELEMENTS OF PHILOSOPHY CONCERN- 
ING BODY," AND IN BRIEFER EXTRACTS 
FROM HIS "HUMAN NATURE" 
AND "LEVIATHAN- 



selected BY 
MARY WHITON CALKINS 



"The world (1 mean . . the whole mass of all things 
that are), is corporeal, that is to say, body ; . . and that 
which is not body is no part of the universe" 



CHICAGO 

THE OPEN COURT PUBLISHING COMPANY 

LONDON AGENTS 

Messrs. Kegan Paul. Trench. Trubner & Co.. Ltd. 

1905 






% 



2 !9Uo 
Cou^ngtu entry 

A AC. M05 



Copyright 1905 

BY 

THE OPEN COURT PUBLISHING CO. 
Chicago 



PREFACE. 

This condensation of the English version of Hobbes's 
book Concerning Body has been made, because the 
work is the completest summary of the metaphysical 
teaching of Hobbes and because there exists no inex- 
pensive reprint or compendium of it. The ethical and 
social doctrines of Hobbes may be readily studied at 
first hand, by the aid of modern editions of the Le- 
viathan or of volumes of selections from the writings 
of Hobbes; but for his strictly metaphysical teaching 
one must now have recourse to the volumes of the 
Molesworth edition. Teachers of modern philosophy 
who believe, with the writer, that the study of original 
texts is of incomparable value to the student must have 
been puzzled in their efforts to be just to the claims of 
materialism. Convenient expositions of idealism are 
readily found in the editions of Berkeley's Principles 
and Dialogues. But no historically important sum- 
mary of materialistic doctrine has, so far, been accessi- 
ble. This volume aims to supply the need and also to 
give an adequate impression of the Elements of Phi- 
losophy Concerning Body. To gain the latter end, 
chapters have been included from all four Parts of the 
work, and the headings of omitted chapters have been 
printed in full. To represent adequately the doctrine 
of Hobbes, it has been necessary to add to the formula- 
tion of materialism, as contained in the Concerning 
Body, (i) the argument for materialism, from the 

iii 



iv PREFACE. 

alleged unreality of consciousness, as it appears in 
chapter II. of Human Nature; and (2) the corollary 
from materialism, the teaching that spirit is a form of 
body, from the later chapters of Leviathan. 

The only portions of this volume which duplicate 
recent reprints from Hobbes are chapters 1, 6, 25, and 
a few scattered passages from Concerning Body, chap- 
ter 2 of Human Nature, and the brief selections from 
Leviathan. The text is that of Molesworth who, 
save in the case of capitals and of spelling, follows the 
early editions. Four obvious misprints, including 
two misplaced Greek accents, have been changed. 

The extracts from the Latin work De Corpore, of 
which Concerning Body is a version, are offered in rec- 
ognition of the fact that Hobbes himself did not make 
the translation, and that the English version, spite of his 
revision, has not the authority of an original work. It 
is a pity not to reprint the Latin original, in place of 
the English version ; but, unhappily, young American 
students either are not, or think that they are not, 
able to read Latin philosophical texts. By way of a 
slight protest against this form of academic illiteracy, 
no life of Hobbes is here printed save the autobiog- 
raphy, in Latin verse, written at the age of eighty-four 
by the vigorous old philosopher. Biographical and 
historical discussions will be found in the works by 
Robertson, Stephen and Sneath, quoted on page xxv., 
in the Bibliographical Note. For an exposition of 
the philosophy of Hobbes, all readers are referred to 
Hobbes himself. 

M. W. C. 



CONTENTS 

T. Hobbes Malmesburiensis Vita vii 

Topical List of the Writings of Hobbes .... xviii 
Bibliographical Note xxv 

Elements of Philosophy Concerning Body. 

Title Page I 

Translator's Preface 2 

The Author's Epistle to the Reader 3 

PART FIRST OR LOGIC. 

Chap. I.— Of Philosophy 5 

*Chap. II.— Of Names 15 

♦Chap. III. — Of Proposition 16 

♦Chap. IV.— Of Syllogism 16 

*Chap. V. — Of Erring, Falsity, and Captions ... 17 

Chap. VI.— Of Method 17 

PART SECOND, OR THE FIRST GROUNDS OF PHILOSOPHY. 

Chap. VII.— Of Place and Time 43 

Chap. VIII.— Of Body and Accident 52 

Chap. IX.— Of Cause and Effect 69 

Chap. X. — Of Power and Act 76 

Chap. XI. — Of Identity and Difference 80 

Chap. XII.— Of Quantity 86 

♦Chap. XIII.— Of Analogism, or the Same Proportion 92 
♦Chap. XIV.— Of Strait and Crooked, Angle and 

Figure 92 

PART THIRD, OF THE PROPORTIONS OF MOTIONS AND 
MAGNITUDES. 

Chap. XV.— Of the Nature, Properties, and Divers 

Considerations of Motion and Endeavour . . 95 



*Only the heading of this chapter is reproduced. 

V 



vi CONTENTS 

*Chap. XVI. — Of Motion Accelerated and Uniform, 

and of Motion by Concourse 106 

*Chap. XVII. — Of Figures Deficient 106 

*Chap. XVIII.— Of the Equation of Strait Lines with 
the Crooked Lines of Parabolas and other Fig- 
ures made in imitation of Parabolas .... 107 
*Chap. XIX. — Of Angles of Incidence and Reflection, 

equal by Supposition 108 

*Chap. XX. — Of the Dimension of a Circle, and the Di- 
vision of Angles or Arches 109 

*Chap. XXI. — Of Circular Motion 109 

*Chap. XXII.— Of other Variety of Motion .... no 
*Chap. XXIII. — Of the Centre of Equiponderation of 

Bodies pressing downwards in Strait Parallel Lines III 
*Chap. XXIV.— Of Refraction and Reflection . .112 

PART FOURTH, OR THE PHENOMENA. OF NATURE. 

Chap. XXV. — Of Sense and Animal Motion . . . 113 

*Chap. XXVI.— Of the World and of the Stars . . 134 

Chap. XXVII.— Of Light, Heat, and of Colours . . 134 
*Chap. XXVIII.— Of Cold, Wind, Hard, Ice, Restitu- 
tion of Bodies bent, Diaphanous, Lightning and 

Thunder, and of the Heads of Rivers .... 140 

Chap. XXIX. — Of Sound, Odour, Savour, and Touch 141 

Chap. XXX.— Of Gravity 153 

The Doctrine of Hobbes Concerning the Unreality 

of Consciousness. 

Human Nature — Chap. II 157 

The Doctrine of Hobbes Concerning the Na- 
ture of Spirit and of God. 

Leviathan, Chap. XI. (in part) 165 

Chap. XII 166 

Chap. XXXI. (in part) 171 

Chap. XXXIV. (in part) 173 

Selected Passages from De Corpore. 

183 



'Only the heading of this chapter is reproduced. 



T. HOBBES 

MALMESB URIENSIS 

VITA, 

SCRIPTA ANNO MDCLXXII. 

Birth Natus erat noster servator Homo-Deus annos 

Mille et quingentos, octo quoque undecies. 
Stabat et Hispanis in portubus inclyta classis 

Hostilis, nostro mox peritura mari : 
Primo vere; dies et quintus inibat Aprilis: 
Illo vermiculus tempore nascor ego, 
Birthplace In Malmesburia ; baptisma a patre ministro 
Accepi, et nomen mi dedit ille suum. 
Oppidulum parvum est, habuit sed multa relatu 

Digna, atque imprimis coenobium celebre, 
Et castrum, melius nisi sint duo castra vocanda, 

Colle sita, et bino flumine cincta fere. 
Concilium regni binis burgensibus auget; 

Nunc quoque priscus honor permanet ille loci. 
Hie et Athelstani conduntur nobilis ossa, 
Atque super tumulum saxeus ipse jacet. 
Praemia virtutis populo dedit ille, propinquos 
Sanguine Danorum qui madefecit agros : 
Study Hue et ab Aldhelmo deducta est musa Latina, 

Hie habuit primam lingua Latina scholam. 
Non est ut patriae pudeat ; sed tempus iniquum 

Conqueror, et mecum tot quoque nata mala. 
Fama ferebat enim diffusa per oppida nostra, 

Extremum genti classe venire diem. 
Atque metum tantum concepit tunc mea mater, 
Ut pareret geminos, meque metumque simul. 
Hinc est, ut credo, patrios quod abominor hos- 
tes, 
Pacem amo cum musis, et faciles socios. 
Disco loqui quatuor, totidem legere, et nume- 
rare, 
Non bene praeterea fingere literulas. 
vii 



Vlll 



VITA THO. HOBBES. 



Oxford 



Service of 
Duke of 
Devonshire 



Sex annis ad verba steti Graecae atque Latinae, 

Et decimo quarto mittor ad Oxonium. 
Hue Magdalenae veniens admittor in aulam, 

Inque ima logicae classe locatus eram. 
Et praelectori cum primis sedulus adsum; 

Is licet imberbis cum gravitate legit, 
Barbara, celarent, darii, ferio, baralypton, 

Hos, dicebat, habet prima figura modos. 
Ccesare, camestres, festino, baroco, darapti, 

Haec etiam totidem stat variata modis. 
Felapton, disamis } datisi, bocardo, ferison, 

Sunt rursus totidem legitimique modi. 
Quos tarde disco, disco tamen, abjicioque, 

Admittorque meo quaeque probare modo. 
Admoveor physicae, conflataque cuncta magister 

Materia et forma, ut partibus, esse docet; 
Et species rerum, volitando per sera, formas 

Donare hinc oculis, auribus inde sonos. 
Multos effectus tribuit syn et antipathies, 

Et supra captum talia multa meum. 
Ergo ad amcena magis me verto, librosque re- 
volve, 

Queis prius instructus, non bene doctus eram. 
Pascebamque animum chartis imitantibus or- 
bem, 

Telluris faciem, et sydera picta videns : 
Gaudebam soli comes ire, et cernere cunctis 

Terricolis ustos qua facit arte dies. 
Quoque Dracus filo Neptunum, Candisiusque 

Cinxerunt medium ; quseque adiere loca * 
Atque hominum exiguos, si possem, cernere 
nidos, 

Et picta ignotis monstra videre locis. 
Tempore sed justo cum Baccalaureus Artis 

Essem (namque hie est primus in arte gra- 
dus) 
Oxonium linquo, servitum me fero in amplam 

Gentis Candisiae conspicuamque domum; 
Rectorisque aulas commendat Epistola nostras: 

Accipior, placita conditione steti: 



VITA THO. HOBBES. 



IX 



Study of 
classics 



Travel 



Atque adolescenti mox applicor ipse adolscens : 

Tunc patris imperio subditus ille fuit. 
Huic ego servivi bis denos gnaviter annos; 

Non Dominus tantum, verum et amicus erat. 
Pars erat ilia meae multo dulcissima vitse, 

Et nunc ssepe mihi somnia grata facit. 
Ille per hoc tempus mihi praebuit otia, libros 

Omnimodos studiis praebuit ille meis. 
Vertor ego ad nostras, ad Graecas, atque Latinas 

Historias ; etiam carmina saepe lego. 
Flaccus, Virgilius, fuit et mihi notus Homerus, 

Euripides, Sophocles, Plautus, Aristophanes, 
Pluresque; et multi Scriptores Historiarum: 

Sed mihi prae reliquis Thucydides placuit. 
Is Democratia ostendit mihi quam sit inepta, 

Et quantum coetu plus sapit unus homo. 
Hunc ego scriptorem verti, qui diceret Anglis, 

Consultaturi rhetoras ut fugerent. 
Urbes externas eadem per tempora vidi, 

Germanas, Francas, Ausoniasque adii. 
Mox Dominum morbo devictum vita reliquit, 

Extremo (ut credas) sed reditura die. 
Ante tamen fecit mihi ne servire necesse 

Esset, qui modice vivere suetus eram. 
Deinde domo placita nimium neglectus abivi, 

Parisiisque moror mensibus octodecim. 
Inde mei Domini revocor praeceptor ut essem 

Nato ; Devoniae tunc Comes ille fuit. 
Hunc Romanarum sensus cognoscere vocum; 

Jungere quoque decet verba Latina modo ; 
Fallere quaque solent indoctos rhetores arte ; 

Quid facit orator, quidque poeta facit; 
Et demonstrandi docui praecepta, globique 

Mundani faciem, multiplicesque gyros. 
Litibus et finem, faciunt quas plus, minus, et 
Par, 

Qua posset usta ponere lege dedi. 
Hses ilium docui per septem sedulos annos; 

Ille celer didicit, retinuitque memor. 



VITA THO. HOBBES. 



Second 
journey 



Study of 
physics 



Study of 
philosophy 
and 
psychology 



Nec tamen hoc tempus libris consumpsimus 
omne, 

Ni mundum libri dixeris esse loco. 
Italiae multas, Gallorum et vidimus urbes; 

Secessus dulces vidimus Allobrogum. 
Ast ego perpetuo naturam cogito rerum, 
Seu rate, seu curru, sive ferebar equo. 
Et mihi visa quidem est toto res unica mundo 

Vera, licet multis falsificata modis: 
Unica vera quidem, sed quae sit basis earum 

Rerum, quas falso dicimus esse aliquid; 
Qualia somnus habet fugitiva, et qualia vitris 

Arbitrio possum multiplicare meo; 
Phantasiae, nostri soboles cerebri, nihil extra; 

Partibus internis nil nisi motus inest 
Hinc est quod, physicam quisquis vult discere, 
motus 

Quid possit, debet perdidicisse prius. 
Ergo materiae motusque arcana reculudo; 

Sic tempus vacuum fallo per Italiam. 
Scribo nihil, facio adversaria nulla, magistra 

Quae docuit, praesens nam mihi semper erat. 
Linquimus Italiam, rursusque redimus ad alta 

Mcenia Lutetiae, tectaque magnifica. 
Hie ego Mersennum novi, communico et illi 

De rerum motu quae meditatus eram. 
Is probat, et multis commendat; tempore ab 
illo 

Inter philosophos et numerabar ego. 
In patriam rursus post menses octo reversus, 

De conectendis cogito notitiis. 
Motibus a variis feror ad rerum variarum 

Dissimiles species, materiaeque dolos; 
Motusque internos hominum, cordisque late- 
bras; 

Denique ad imperii justitiaeque bona. 
His ego me mersi studiis. Nam philosophandi 

Corpus, Homo, Civis continet omne genus. 
Tres super his rebus statuo conscribere libros ; 



VITA THO. HOBBES. xi 

Materiemque mihi congero quoque die. 
Nascitur interea scelus execrabile belli, 

Et veniunt studiis tempora iniqua meis. 
Sexcentesimus et jam quadragesimus annus 

Post millesimum erat virginis a puero, 
Cum patriam invasit morbus mirabilis, unde 

Innumeri e doctis post periere viri. 
Quo quicunque fuit tactus, divina putabat 

Atque humana uni cognita jura sibi. 
Jamque in procinctu bellum stetit. Horreo 
spectans ; 

Meque ad dilectam confero Lutetiam. 
De Cive Postque duos annos edo De Cive libellum, 

Qui placuit doctis, et novus omnis erat ; 
Versus et in varias linguas cum laude legebar, 

Gentibus et late nomine notus eram. 
Laudabat mediis in Erynnibus Anglia, et ill! 

Quorum consiliis cognitus hostis eram 
Sed quod consiliis prcesentibus utile non est, 

Quantumvis justum, quis put at esse bonumf 
De Corpore Inde annis quatuor libri De Corpore forman, 

Qua sit scribendus, nocte dieque puto. 
Comparo corporeas moles ; et cogito rerum 

Visarum formas quid variare potest. 
Quaero quibus possim rationis Protea vinclis 

Stringere, fassurum qua tegit arte dolos. 
Adfuit e Minimis Mersennus, fidus amicus; 

Vir doctus, sapiens, eximieque bonus. 
Cujus cella scholis erat omnibus anterferenda ; 

Professorum omnes ambitione tument. 
Illi portabat, si dignum forte porisma 

Reppererat quisquam, principiumve novum. 
Perspicuo et proprio sermone, carente figuris 

Rhetoricis, gnomis, ambitione, dolo, 
Ille dedit doctis, qui vellent, rursus ut illud 

Vel statim possent, vel trutinare domi. 
Edidit e multisque inventis optima quaeque; 

Signans authoris nomine quidque sui. 
Circa Mersennum convertebatur ut axem 

Unumquodque artis sidus in orbe suo. 



xii VITA THO. HOBBES. 

Saevierat bellum quatuor civile per annos, 

Anglos, Hibernos triverat atque Scotos. 
Perfidaque in castris mansit Fortuna scelestis: 

Diffugere via qua potuere probi. 
Ipse haeres regni Carolus, comitante caterva 

Armis clarorum et nobilitate virum, 
Lutetiam venit, expectans dum tempora iniqua 

Transirent, populi desineretque furor. 
Tunc ego decreram De Corpore scribere librum, 

Cujus materies tota parata fuit. 
Sed cogor differre ; pati tot tantaque fceda 

Apponi jussis crimina, nolo, Dei. 
Divinas statuo quam primum absolvere leges; 

Idque ago paulatim, sollicitusque diu. 
Namque mathematicae studiis dum Principi 
adessem, 

Non potui studiis semper adesse meis. 
Dein per sex menses morbo decumbo, propin- 
quae 

Accinctus morti; nee fugio, ilia fugit. 
Leviathan Perfeci librum patrio sermone ; ut ab Anglis 

Posset saepe meis, utiliterque legi: 
Londinoque typis celer evolat in regiones 

Vicinas, notus nomine Leviathan. 
Militat ille liber nunc regibus omnibus, et qui 

Nomine sub quovis regia ura tenent. 
Interea regem vendit Scotus, et necat Anglus; 

Jus regni Carolus jamque Secundus habet, 
Lutetiae residens. Vim regni turba rebellis 

Occupat, et populum jam sine lege regit, 
Et nomen (quamvis pauci) sibi Parliamenti 

Sumens, se satiat sanguine nobilium ; 
Dejiciunt mitras, nee firmant Presbyteratum ; 

Clerica nil illic profuit ambitio. 
Exile Lutetiam ad regem multus venit inde scholans 

Expulsus patria, tristis, egenus, onus. 
Hue fuit usque meis studiis pax, multiplicata 

Dum facerent annos octo per octo meos; 
Sed meus ille liber, simul atque scholaribus illis 

Lectus erat, Jani dissiluere fores. 



VITA THO. HOBBES. x 

Nam Regi accusor falso, quasi facta probarem 

Impia Cromwelli, jus scelerique darem. 
Creditur; adversis in partibus esse videbar; 

Perpetuo jubeor Regis abesse domo. 
Tunc venit in mentem mihi Dorislaus,* et 
Ascham ;* 

Tanquam proscripto terror ubique aderat. 
Nee de rege queri licuit. Nam tunc adolescens 

Credidit Me, quibus credidit ante pater. 
Return In patriam redeo tutelae non bene certus, 

Sed nullo potui tutior esse loco: 
Frigus erat, nix alta, senex ego, ventus acer- 
bus; 

Vexat equus sternax et salebrosa via. 
Londinum veniens, ne clam venisse viderer, 

Concilio Status conciliandus eram. 
Quo facto, statim summa cum pace recedo, 

Et sic me studiis applico, ut ante, meis. 
Solum regnabat tunc nomine Parliamentum; 

Praesul erat nullus, Presbyterusque nihil. 
Omnia miles erat, committier omnia et uni 

Poscebat ; tacite Cromwell is unus erat. 
Regia conanti calamo defendere jura, 

Quis vitio vertat regia jura petens? 
Scribere cuique fuit libertas, quod sibi visum 

Esset, contento vivere more loci. 
Leviathan clerum at totum mihi fecerat hos- 
tem; 

Hostis Theologum nidus uterque fuit. 
Nam dum Papalis Regni contrecto tumorem, 

Hos, licet abscissos, lsedere visus eram. 
Contra Leviathan, primo, convicia scribunt, 

Et causa, ut tanto plus legeretur, erant. 
Firmius inde stetit, spero stabitque per omne 

iEvum, defensus viribus ipse suis. 
Justitiae mensura, atque ambitionis elenchus, 

Regum arx, pax populo, si doceatur, erit. 



* Regicidae infames; quorum hie apud Hispanos, ilk 
apud Foederatos Belgas a Parliamentariis legatus, a 
regiis confossi perierunt. 



XIV 



VITA THO. HOBBES. 



Controversy 

on 

mathematics 



Six lessons 



Problems 



Ante duos minima prsemisi mole libellos; 

Sed nee inest parvis gratia parva libris. 
Ule* docet motus animi et phantasmata sensus, 

Nee sanos patitur spectra timer e viros: 
Alterf at Imperii sanctissima jura repandit, 

Quaeque rudes populos vincula sacra tenent. 
Tandem etiam absolvo librum De Corpore, 
cujus 

Materies simul et forma geometrica est. 
Tunc venit in lucem, tota plaudente caterva 

Algebristarum, Wallisii algebrica, 
Ilia Geometriae pestis, quae cceperat ante 

Annos plus centum, nunc et ubique furit. 
Ars fuerat numeros quaesitos inveniendi, 

Quam docuit Cheber, et quam Diophantus 
habet. 
Deinde per hanc artem solam problemata solvi 

Posse geometriae cuncta Vieta docet. 
Addidit Oxoniae Praelector Savilianus 

Wallisius multo nobile dogma magis : 
Nempe infinitae molis finem esse, et habere 

Finitum partes et sine fine datas : 
Quae duo fecerunt insanos dogmata, quotquot 

Festinaverunt esse geometrici. 
Haec mihi causa satis scribendi est justa libelli, 

(Annos natus eram septuaginta duos) 
In quo, Colloquiis ego Sex non molliter istos 

Tango geometras, ut meruere, novos ; 
Sed nil profeci, magnis authoribus error 

Fultus erat; cessit sic medicina malo. 
Tunc quoque scribo duos patrio sermone libellos 

Contra Bramhallum. Quaestio sola fuit, 
Cujus ad arbitrium volumus, nostrumne, Deine : 

Ille scholam sequitur, sed mihi dux ratio est. 
Sex quoque post paulo scripsi Problemata, 
librum 

Exiguum, at purae fonticulum physicae. 



* Liber de Natura Humana. 
t Lib. de Corpore Politico. 



VITA THO. HOBBES. xv 

Nam doceo natura locis qua dejicit arte 

Sublimes lapides, res aliasque graves; 
Qua situla sol haurit aquas; ut frigora ventus 

Efficit; et venti qua ratione volant: 
Quo pendent steriles, volitantque per aera nubes, 

Quo fulcro gravida? destituente ruunt; 
Et quo consistunt durorum glutine partes, 

Duraque quae rursus mollia causa facit ; 
Unde fragor ccelo, qua nix glaciesque fit arte; 

Excussusque altis emicat ignis aquis ; 
Quid res exiguas conjungit in aere sparsas, 

Et calidum Phcebus qua ratione facit; 
Herculeusque lapis ferrum quibus attrahit 
uncis, 

Observatque suae matris utrumque polum; 
Cur mare non aequis ad littora volvitur undis ; 

Anno, mense, die quoque, bis auget aquas ; 
Et quare, vento duce, navis it obvia vento ; 

Haec habet et monstrat parvulus ille liber. 
Et valitura puto cum tempore; quandoquidem 
nunc 

Inter tot Momos irreprehensa manent. 
JEris et parvo naturam scribo libello 

Adversus quandam machinam inanificam. 
Tunc physicam linquens, ad amata mathemata 
vertor ; 

Namque meo tandem cesserat hostis agro. 
Tantum non lapidem potuissem vera docere. 

Clamosas speret nemo docere scholas. 
De Principiis At De Principiis alium tamen edo libellum, 

Fecique ut posset clarius esse nihil. 
In quo naturam rationis ita explico, ut illam 

Nemo non claram diceret atque" probam. 
Hac mihi parte fuit victoria cognita cunctis, 

Dissimulant aliis vulnera magna locis ; 
Deficiunt animis, sed deficientibus insto, 

Culminaque inscendo summa geometriae. 
Namque parem cyclum quadrato publico ; nec- 
non 

Jactatum Pythii monstro porisma Dei ; 



XVI 



VITA THO. HOBBES. 



Demonstrata prius, sed non rationibus iisdem, 

Sperabam methodo vincere posse nova. 
Sed nil profeci, densis umbonibus obstant, 

Cedere quos puduit, semi-mathematici. 
Ergo meam statuo non ultra perdere opellam, 

Indocile expectans discere posse pecus. 
Rosetum, Deinde librum scribo, quern nomine dico Rose- 
turn, 

Praecipuo densum flore geometriae. 
Wallisius contra pugnat ; victusque videbar 

Algebristarum Theologumque scholis. 
Et simul eductus castris exercitus omnis 

Pugnae securus Wallisianus ovat; 
Quern cum vidissem salebroso insistere campo, 

Stabat ubi radix densa, molesta, tenax, 
Pugna placet, vertor ; numerum licet infinitum 

Temporis in puncto dissipo, sterno, fugo. 
Bella mea audisti. Quid vis tibi dicier ultra? 

An quam dives, id est, quam sapiens f uerim ? 
Anne refert quot agros habui, quot millia num- 
mum? 

Si percontator forte rogabit et hoc, 
Exiguus mihi fundus erat propriusque relictus 

Quern fratri dono, ductus amore, dedi. 
Parva superficies, sed millia multa ferebat 

Granorum tritici, nam bona terra fuit. 
Longa satis votis regum ; et nisi tota deorsum 

Tensa foret, Rex nunc magnus haberer ego. 
Ut primum belli sensi civilis odorem, 

Et populum ventos vidi agitasse levem: 
Quaero locum studiis, et vitae commodiorem, 

Hinc me Parisios transfero remque meam. 
Quingentae mihi erat numerata pecunia librae, 

Cum fugiens patriae littora linquo meae: 
Legacy His aliae paulo post accessere ducentae.* 

Et simul immensus perpetuusque dolor. 
(Godolphine jaces; purae rationis amator, 

Justitiae et Veri miles amande, vale.) 



Ex Legato Sydn. Godolphini. 



VITA THO. HOBBES. xvii 

Venit et e patria mihi pensio certa quotannis, 

Bis* quadragintis constitit ilia libris. 
from Deinde redux mihi Rex concessit habere quo- 
King tannis 

Centum alias libras ipsius ex loculis, 
Dulce mihi donum. Convicia sperno aliorum, 

Quando teste ipso judicor esse probus. 
His ego contentus vivo, nee praefero plura; 

Quis vellet sanus re minor esse sua? 
Rem, si quando lubet, per vestros supputo 
Sousos, 

Ut fiat major: si neque sic satis est, 
Per Maravedisios numero, videorque beatus 

Croesos et Crassos vincere divitiis. 
Ipse meos nosti, Verdusi candide, mores, 

Et tecum cuncti qui mea scripta legunt. 
Nam mea vita meis non est incongrua scriptis : 

Justitiam doceo, justitiamque colo. 
Improbus esse potest nemo qui non sit avarus, 

Nee pulchrum quisquam fecit avarus opus. 
Octoginta ego jam complevi et quatuor annos: 

Pene acta est vitae fabula longa meae. 



* Ex munere Comitis Devonia. 



TOPICAL LIST OF THE WRITINGS OF 
HOBBES. 



The dates and the Latin titles are transferred 
from the catalogue of Ant a Wood, as reprinted in 
Molesworth's edition of the Opera Latina (cited as 
Op. Lat.), Vol. I. The English titles are those of 
Molesworth's edition of the English works (cited as 
E. W.), except when these conflict with the titles 
quoted by Robertson from the early editions. All 
works, unless otherwise indicated, were published in 
London. 

I. Writings on Metaphysics. 



i 641. Objections in Cartesii de prima Philosophia 
Meditationes. 

Published in all the early editions of Descartes's 
Meditations, Paris and Amsterdam. 

1655. Elementa Philosophise Sectio prima de Corpore, 

8vo, 1655. Op. Lat. Vol. I. 

1656. Elements of Philosophy, The First Section Con- 

cerning Body. E. W. I. 

A translation, not by Hobbes, of the De Corpore. 
Cf. pp. ii. and 183 of this volume. 

See, also, for metaphysical discussion, Leviathan (esp. 
chapters 12, 31, 34) ; the ethical writings ; An Answer 
to a Book ... by Dr. Bramhall. 

II. Writings on Mathematics and Physics. 



1644. Tractatus Opticus. Op. Lat. V. 

Published by V. 
Physico-Matl 

1655. D e Corpore. 



Published by Mersenne, in 1644, in his Cogitata 
Physico-Mathematica. 



xvm 



THE WRITINGS OF HOBBES. xix 

1656. Concerning Body. 

These two works, already quoted by their full titles, 
contain the mathematical as well as the meta- 
physical doctrine of Hobbes. This follows nat- 
urally from his conviction, that " every part of 
the universe is body," for, if this be granted, the 
mathematical laws of the physical world are the 
principles of all reality. Hobbes, however, de- 
spite his pretensions, was never other than an 
amateur in mathematics; and the mathematical 
chapters of De Corpore, along with much irrele- 
vant matter, contain one colossal blunder: the at- 
tempt (C. XX.) at squaring the circle. The error 
was exposed at once by Wallis, Savilian professor 
of geometry at Oxford, in his Elenchus Geomet- 
ries Hobbiana. This work was the starting-point 
of a bitter controversy, lasting more than twenty 
years. So far as the mathematical issues were 
concerned, Hobbes was always in the wrong; but 
he never acknowledged defeat, and returned with 
courage worthy of a better cause, again and again 
to the unequal struggle. (Cf. esp. Robertson's 
" Hobbes," pp. 167 seq.) It should, however, be 
noted that he modified the mathematical chapters, 
both in the later editions of De Corpore (followed 
in Molesworth's Op. Lat., which are based on the 
collected edition of 1668) and also in the English 
version, Concerning Body. All the titles in this 
section are of works concerned in this discussion. 
Unless otherwise described, all are to be found 
either in Op. Lat. IV. or in E. W. VII. 

1656. Six Lessons to the Professors of the Mathe- 

matics, ... in the Chairs set up by 
. . . Sir Henry Savile in the University 
of Oxford. 

1657. STirMAI or Marks of the Absurd Geometry, 

Rural Language, Scottish Church Politics and 
Barbarisms of John Wallis. 

1660. Examinatio et Emendatio Mathematicae Hodier- 

nae. 

1661. Dialogus Physicus, sive de Natura 2Er\s. 



xx THE WRITINGS OF HOBBES. 

1 66 1. De Duplicatione Cubi, Paris. 

Molesworth does not print this in the original 
French, but only in the modified English form, 
as the concluding pages of the Dialogus Physicus. 

1662. Problemata Physica, una cum Magnitudine Cir- 

culi. 

1666. De Principiis et Ratiocinatione Geometrarum. 

1669. Quadratura Circuli, Cubatio Sphaerse, Dupli- 
catio Cubi; una cum Responsione ad Objec- 
tions Geometrise Professoris Saviliani. 

1 67 1. Rosetum Geometricum, . . . cum Censura 
brevi Doctrinae Wallisianse de Motu. Op. 
LatV. 

1 67 1. Three Papers Presented to the Royal Society 

against Dr. Wallis. 

1672. Lux Mathematica. Op. Lat. V. 

1672. Principia et Problemata aliquot geometrica ante 
desperata . . . Op. Lat. V. 

1678. Decameron Physiologicum, or Ten Dialogues of 
Natural Philosophy. 

(posthumous works.) 

1682. Seven Philosophical Problems and Two Propo- 
sitions of Geometry. 

A shortened translation of Problemata Physica, 
1662. 

III. Writings on Psychology. 
1650. Human Nature. E. W. IV. 

The logical foundation both of Hobbes's metaphysics 
and of his political philosophy. Actually the first 
of his systematic works, written in 1640 and at 
that time combined with the De Corpore Politico, 
under the title, The Elements of Law, Natural and 
Politique. (Cf. Robertson, " Hobbes," p. 51 and 
p. 67, Note.) 



THE WRITINGS OF HOBBES. xxi 

1657. De Homine, sive Elementorum Philosophise 
Sectio Secunda. Op. Lat. II. 

An ill proportioned work, less complete than Human 
Nature and containing many, chiefly irrelevant, 
chapters on optics. 

See also, for psychological discussion: Leviathan, Pt. 
I. ; De Corpore, Pt. IV. ; Concerning Body, Pt. IV. ; 
Decameron Physiologicum. 

IV. Writings on " Civil Philosophy (or Poli- 
tics). " 

1642. Elementorum Philosophise Sectio Tertia De 
Cive. Paris. 

Privately printed. Re-printed, in 1647, with altered 
title, thus: 

1647. Elementa Philosophica de Cive. Amsterdam. 
Op. Lat. II. 

165 1. Philosophical Rudiments concerning Govern- 
ment and Society. E. W. II. 

1650. De Corpore Politico, or the Elements of Law, 

Moral and Politic. E. W. IV. 

Written in 1640 (Cf. Note, above, on Human Na- 
ture.) As compared with the De Cive, this work 
lays less emphasis on the power of the state in 
ecclesiastical matters. 

165 1. Leviathan: Or, the Matter, Form and Power of 

a Commonwealth, Ecclesiastical and Civil. 
E. W. III. 

The most popular, forcible and detailed discussion of 
the political theory of Hobbes, prefixed by several 
chapters on psychology. 

1668. Leviathan. Amsterdam. Op. Lat. III. 

A translation, by Hobbes himself, into Latin. The 
Latin version omits and alters certain portions of 
the English original. It included: 



xxii THE WRITINGS OF HOBBES. 

1668. Appendix ad Leviathan. Amsterdam. Op. 
Lat. III. 

The Appendix sets forth (1) that the teaching of 
Leviathan is not heretical and (2) that there re- 
mains in England no court of heresy. 

(POSTHUMOUS WORKS.) 

For the following works, Hobbes did not succeed in 
obtaining the censor's license : — 

1680. Behemoth : The History of the Causes of the 
Civil Wars of England . . . from the Year 
1640 to the Year 1660. E. W. VI. 

Written about 1668. Several unauthorized and in- 
accurate editions appeared before 1680. 

1680. An Historical Narration concerning Heresy and 

the Punishment Thereof. (London?) E. 
WAV. 

Written about 1666, after the abortive parliamentary 
proceedings against Leviathan. 

1 68 1. A Dialogue between a Philosopher and a Student 

of the Common Laws of England. E. W. VI. 

Written about 1666. 

1682. An Answer to a Book Published by Dr. Bram- 

hall . . . called Catching of the Le- 
viathan. E. W. IV. 

Written in 1668. A refutation of Bramhall's charge, 
" that the Hobbian principles are destructive to 
Christianity and to all religion." 

1688. Historia Ecclesiastica Romana, Poema . . . 
ubi de Superstitionis Origine, progressu, &c. 
Op. Lat. V. 

Written, about 1670. An English version was pub 
lished in 1722. 



THE WRITINGS OF HOBBES. xxiii 

V. Writings on Ethics. 
1654. Of Liberty and Necessity. E. IV. IV. 

Written in in 1646, as part of a private discussion 
with Bishop Bramhall; published without the con- 
sent of Hobbes. (Cf. Robertson, " Hobbes," p. 
163 seq.) 

1656. The Questions concerning Liberty, Necessity 
and Chance, Clearly Stated and Debated be- 
tween Dr. Bramhall, Bishop of Derry, and 
Thomas Hobbes, of Malmesbury. E. W. V. 
See, also, Writings on Civil Philosophy. 

VI. Writings on Rhetoric and on Miscellaneous 
Subjects. 

1636. De Mirabilibus Pecci liber. 

Account of an excursion round Derbyshire Peak. 
Written before 1628, Op. Lot. V. 

1650. The Answer of Mr. Hobbes to Sir William 
Davenant's Preface before Gondibert. 

A letter on the nature of poetry, apropos of the poet 
laureate's heroic poem, Gondibert, E. W. IV. 

1669. Letter to the Right Honorable Edw. Howard. 

Published as prefix to Mr. Howard's poem, The 
British Princes. 

(POSTHUMOUS WORKS.) 

1681. The Whole Art of Rhetoric. E. W. VI. 

An English abstract of that Latin version of Aris- 
totle's Rhetoric, dictated between 1630 and 1640, 
by Hobbes, to his pupil, the young Earl of Devon- 
shire. To this is added, in the edition of 1681, 
short treatises on: 



xxiv THE WRITINGS OF HOBBES. 

The Art of Rhetoric, 
The Art of Sophistry. 

VII. Translations. 

1628. Eight Books of the Peloponnesian War, written 
by Thucydides . . . Interpreted with Faith 
and Diligence immediately out of the Greek. 
E. W. VIII. and IX. 

1674. Voyage of Ulysses. 

A rhymed translation of Odyssey, Bks. IX.-XII., 
later incorporated in the complete translation: 

1675. The Iliads and Odysses of Homer. Translated 

out of Greek into English. With a large 
preface concerning the Virtues of an Heroic 
Poem. E. W. X. 



VIII. Personal Writings. 

1662. Considerations upon the Reputation, Loyalty, 
Manners and Religion of Thomas Hobbes. 
E. W. IV. 

A reply to the personal charges of Wallis's Hobbius 
Heautontimorumenos. 

1674. Epistola ad Antony a Wood. (London?) Not 
included in Op. Lat. 

A protest against Dean Fell's abuse of Hobbes in 
the translation of Wood's History and Antiquities 
of Oxford. 

1679. Vita Ejus Latino Carmine, Op. Lat. I. 



THE WRITINGS OF HOBBES. xxy 

(posthumous works.) 
1 68 1. T. Hobbes Malmesburiensis Vita. Op. Lat. I. 

A prose life, attributed to Hobbes. 

See, also, for personal allusions, all the controversial 
writings of Hobbes; and for a few letters, E. W. 
VII. and Op. Lat. V. 



BIBLIOGRAPHICAL NOTE. 

For references to contemporary criticism of Hobbes, usually 
unsympathetic and often violent, see R. Blackbourne, Vitae 
Hobbianae Auctarium (1681), Op. Lat. I., p. Ixix. seq. 

For references to works of exposition and of criticism, from 
the later seventeenth century onward, see Sneath, " The Ethics 
of Hobbes" (1898), Introduction, p. xii. seq.; Robertson, (1) 
"Hobbes" (1886), chaps. IX. and X., (2) article in Encycl. 
Brit., 9th ed., vol. XII., footnotes. 

The most useful of recent works on the life, writing and 
system of Hobbes include the books, just mentioned, of Rob- 
ertson and of Sneath, and the following: "Hobbes" (1904), 
by Leslie Stephen, and "Hobbes, Leben und Lehre," (Stutt- 
gart, 1896) by F. Tonnies, and Woodbridge, " The Philosophy 
of Hobbes in Extracts and Notes from his Writings" (1903)- 



ELEMENTS OF PHILOSOPHY. 

THE FIRST SECTION, 

CONCERNING BODY, 

WRITTEN IN LATIN 

BY 

THOMAS HOBBES OF MALMESBURY, 

AND 

TRANSLATED INTO ENGLISH. 



THE 
TRANSLATOR TO THE READER. 

If, when I had finished my translation of this first sec- 
tion of the Elements of Philosophy, I had presently 
committed the same to the press, it might have come to 
your hands sooner than now it doth. But as I under- 
took it with much diffidence of my own ability to per- 
form it well ; so I thought fit, before I published it, to 
pray Mr. Hobbes to view, correct, and order it accord- 
ing to his own mind and pleasure. Wherefore, though 
you find some places enlarged, others altered, and two 
chapters, XIII and XX, almost wholly changed, you 
may nevertheless remain assured, that as now I present 
it to you, it doth not at all vary from the author's own 
sense and meaning. ********** 



THE 

AUTHOR'S EPISTLE TO THE READER. 

Think not, Courteous Reader, that the philosophy, 
the elements whereof I am going to set in order, is 
that which makes philosophers' stones, nor that which 
is found in the metaphysic codes ; but that it is the nat- 
ural reason of man, busily flying up and down among 
the creatures, and bringing back a true report of their 
order, causes and effects. Philosophy, therefore, the 
child of the world and your own mind, is within your- 
self ; perhaps not fashioned yet, but like the world its 
father, as it was in the beginning, a thing confused. 
Do, therefore, as the statuaries do, who, by hewing off 
that which is superfluous, do not make but find the 
image. Or imitate the creation : if you will be a phi- 
losopher in good earnest, let your reason move upon 
the deep of your own cogitations and experience ; those 
things that lie in confusion must be set asunder, dis- 
tinguished, and every one stamped with its own name 
set in order ; that is to say, your method must resemble 
that of the creation. The order of the creation was, 
light, distinction of day and night, the firmament, the 
luminaries, sensible creatures, man; and, after the crea- 
tion, the commandment. Therefore the order of con- 
templation will be, reason, definition, space, the stars, 
sensible quality, man; and after man is grown up, sub- 
jection to command. In the first part of this section, 
which is entitled Logic, I set up the light of reason. 
In the second, which hath for title the Grounds of 
3 



4 CONCERNING BODY. 

Philosophy, I distinguish the most common notions by 
accurate definition, for the avoiding of confusion and 
obscurity. The third part concerns the expansion of 
space, that is Geometry. The fourth contains the Mo- 
tion of the Stars, together with the doctrine of sensible 
qualities. 

In the second section, if it please God, shall be han- 
dled Man. In the third section, the doctrine of Sub- 
jection is handled already. This is the method I fol- 
lowed; and if it like you, you may use the same; for 
I do but propound, not commend to you anything of 
mine. But whatsoever shall be the method you will 
like, I would very fain commend philosophy to you, 
that is to say, the study of wisdom, for want of which 
we have all suffered much damage lately. For even 
they, that study wealth, do it out of love to wisdom; 
for their treasures serve them but for a looking-glass, 
wherein to behold and contemplate their own wisdom. 
Nor do they, that love to be employed in public busi- 
ness, aim at anything but place wherein to show their 
wisdom. Neither do voluptuous men neglect philoso- 
phy, but only because they know not how great a pleas- 
ure it is to the mind of man to be ravished in the 
vigorous and perpetual embraces of the most beauteous 
world. Lastly, though for nothing else, yet because 
the mind of man is no less impatient of empty time 
than nature is of empty place, to the end you be not 
forced for want of what to do, to be troublesome to 
men that have business, or take hurt by falling into 
idle company, but have somewhat of your own where- 
with to fill up your time, I recommend unto you to 
study philosophy. Farewell. 

T. H. 



COMPUTATION OR LOGIC. 

CHAPTER I. 

OF PHILOSOPHY. 

i. The Introduction. — 2. The Definition of Philosophy ex- 
plained. — 3. Ratiocination of the Mind. — 4. Properties, what 
they are. — 5. How Properties are known by Generation, and 
contrarily. — 6. The Scope of Philosophy. — 7. The Utility of 
it— 8. The Subject.— 9. The Parts of it— 10. The Epilogue. 

Philosophy seems to me to be amongst men now, 
in the same manner as corn and wine are said to have 
been in the world in ancient time. For from the be- 
ginning there were vines and ears of corn growing 
here and there in the fields ; but no care was taken for 
the planting and sowing of them. Men lived there- 
fore upon acorns ; or if any were so bold as to venture 
upon the eating of those unknown and doubtful fruits, 
they did it with danger of their health. In like man- 
ner, every man brought Philosophy, that is, Natural 
Reason, into the world with him; for all men can 
reason to some degree, and concerning some things: 
but where there is need of a long series of reasons, 
there most men wander out of the way, and fall into 
error for want of method, as it were for want of sow- 
ing and planting, that is, of improving their reason. 
And from hence it comes to pass, that they who con- 
tent themselves with daily experience, which may be 

5 



6 CONCERNING BODY. 

likened to feeding upon acorns, and either reject, or 
not much regard philosophy, are commonly esteemed, 
and are, indeed, men of sounder judgment than those 
who, from opinions, though not vulgar, yet full of 
uncertainty, and carelessly received, do nothing but 
dispute and wrangle, like men that are not well in 
their wits. I confess, indeed, that that part of philoso- 
phy by which magnitudes and figures are computed, is 
highly improved. But because I have not observed 
the like advancement in the other parts of it, my pur- 
pose is, as far forth as I am able, to lay open the few 
and first Elements of Philosophy in general, as so 
many seeds from which pure and true Philosophy may 
hereafter spring up by little and little. 

I am not ignorant how hard a thing it is to weed out 
of men's minds such inveterate opinions as have taken 
root there, and been confirmed in them by the author- 
ity of most eloquent writers; especially seeing true 
(that is, accurate) Philosophy professedly rejects not 
only the paint and false colours of language, but even 
the very ornaments and graces of the same; and the 
first grounds of all science are not only not beautiful, 
but poor, arid, and, in appearance, deformed. Never- 
theless, there being certainly some men, though but 
few, who are delighted with truth and strength of rea- 
son in all things, I thought I might do well to take 
this pains for the sake even of those few. I proceed 
therefore to the matter, and take my beginning from 
the very definition of philosophy, which is this. 

2. Philosophy is such knowledge of effects or 
appearances, as we acquire by true ratiocination from 
the knowledge we have first of their causes or genera- 
tion: And again, of such causes or generations as may 
be from knowing first their effects. 



OF PHILOSOPHY. 7 

For the better understanding of which definition, we 
must consider, first, that although Sense and Memory 
of things, which are common to man and all living 
creatures, be knowledge, yet because they are given us 
immediately by nature, and not gotten by ratiocination, 
they are not philosophy. 

Secondly, seeing Experience is nothing but memory ; 
and Prudence, or prospect into the future time, noth- 
ing but expectation of such things as we have already 
had experience of, Prudence also is not to be esteemed 
philosophy. 

By ratiocination, I mean computation. Now to 
compute, is either to collect the sum of many things 
that are added together, or to know what remains when 
one thing is taken out of another. Ratiocination, 
therefore, is the same with addition and sub str action; 
and if any man add multiplication and division, I will 
not be against it, seeing multiplication is nothing but 
addition of equals one to another, and division nothing 
but a substraction of equals one from another, as often 
as is possible. So that all ratiocination is compre- 
hended in these two operations of the mind, addition 
and substraction. 

3. But how by the ratiocination of our mind, we 
add and substract in our silent thoughts, without the 
use of words, it will be necessary for me to make in- 
telligible by an example or two. If therefore a man 
see something afar off and obscurely, although no 
appellation had yet been given to anything, he will, 
notwithstanding, have the same idea of that thing for 
which now, by imposing a name on it, we call it body. 
Again, when, by coming nearer, he sees the same thing 
thus and thus, now in one place and now in another, 
he will have a new idea thereof, namely, that for which 



8 CONCERNING BODY. 

we now call such a thing animated. Thirdly, when 
standing nearer, he perceives the figure, hears the 
voice, and sees other things which are signs of a ra- 
tional mind, he has a third idea, though it have yet no 
appellation, namely, that for which we now call any- 
thing rational. Lastly, when, by looking fully and dis- 
tinctly upon it, he conceives all that he has seen as one 
thing, the idea he has now is compounded of his for- 
mer ideas, which are put together in the mind in the 
same order in which these three single names, body, 
animated, rational, are in speech compounded into this 
one name, body-animated-rational, or man. In like 
manner, of the several conceptions of four sides, equal- 
ity of sides, and right angles, is compounded the con- 
ception of a square. For the mind may conceive a 
figure of four sides without any conception of their 
equality, and of that equality without conceiving a 
right angle ; and may join together all these single con- 
ceptions into one conception or one idea of a square. 
And thus we see how the conceptions of the mind are 
compounded. Again, whosoever sees a man standing 
near him, conceives the whole idea of that man ; and if, 
as he goes away, he follow him with his eyes only, he 
will lose the idea of those things which were signs of 
his being rational, whilst, nevertheless, the idea of a 
body-animated remains still before his eyes, so that the 
idea of rational is subtracted from the whole idea of 
man, that is to say, of body-animated-rational, and 
there remains that of body-animated; and a while 
after, at a greater distance, the idea of animated will 
be lost, and that of body only will remain; so that at 
last, when nothing at all can be seen, the whole idea 
will vanish out of sight. By which examples, I think, 



OF PHILOSOPHY. g 

it is manifest enough what is the internal ratiocination 
of the mind without words. 

We must not therefore think that computation, that 
is, ratiocination, has place only in numbers, as if man 
were distinguished from other living creatures (which 
is said to have been the opinion of Pythagoras) by 
nothing but the faculty of numbering; for magnitude, 
body, motion, time, degrees of quality, action, concep- 
tion, proportion, speech and names (in which all the 
kinds of philosophy consist) are capable of addition 
and substraction. Now such things as we add or sub- 
stract, that is, which we put into an account, we are said 
to consider, in Greek \oy%e<rd<u, in which language 
also <rv\\oy%c<rOai signifies to compute, reason, or reckon. 

4. But effects and the appearances of things to 
sense, are faculties or powers of bodies, which make 
us distinguish them from one another; that is to say, 
conceive one body to be equal or unequal, like or unlike 
to another body; as in the example above, when by 
coming near enough to any body, we perceive the mo- 
tion and going of the same, we distinguish it thereby 
from a tree, a column, and other fixed bodies ; and so 
that motion or going is the property thereof, as being 
proper to living creatures, and a faculty by which they 
make us distinguish them from other bodies. 

5. How the knowledge of any effect may be gotten 
from the knowledge of the generation thereof, may 
easily be understood by the example of a circle : for if 
there be set before us a plain figure, having, as near as 
may be, the figure of a circle, we cannot possibly per- 
ceive by sense whether it be a true circle or no; than 
which, nevertheless, nothing is more easy to be known 
to him that knows first the generation of the pro- 
pounded figure. For let it be known that the figure 



io CONCERNING BODY. 

was made by the circumduction of a body whereof one 
end remained unmoved, and we may reason thus; a 
body carried about, retaining always the same length, 
applies itself first to one radius, then to another, to a 
third, a fourth, and successively to all ; and, therefore, 
the same length, from the same point, toucheth the 
circumference in every part thereof, which is as much 
as to say, as all the radii are equal. We know, there- 
fore, that from such generation proceeds a figure, from 
whose one middle point all the extreme points are 
reached unto by equal radii. And in like manner, by 
knowing first what figure is set before us, we may 
come by ratiocination to some generation of the same, 
though perhaps not that by which it was made, yet 
that by which it might have been made; for he that 
knows that a circle has the property above declared, 
will easily know whether a body carried about, as is 
said, will generate a circle or no. 

6. The end or scope of philosophy is, that we may 
make use to our benefit of effects formerly seen; or 
that, by application of bodies to one another, we may 
produce the like effects of those we conceive in our 
mind, as far forth as matter, strength, and industry, 
will permit, for the commodity of human life. For 
the inward glory and triumph of mind that a man may 
have for the mastering of some difficult and doubtful 
matter, or for the discovery of some hidden truth, is 
not worth so much pains as the study of Philosophy 
requires ; nor need any man care much to teach an- 
other what he knows himself, if he think that will be 
the only benefit of his labour. The end of knowledge 
is power; and the use of theorems (which, among 
geometricians, serve for the finding out of properties) 
is for the construction of problems; and, lastly, the 



OF PHILOSOPHY. u 

scope of all speculation is the performing of some 
action, or thing to be done. 

7. But what the utility of philosophy is, especially 
of natural philosophy and geometry, will be best un- 
derstood by reckoning up the chief commodities of 
which mankind is capable, and by comparing the man- 
ner of life of such as enjoy them, with that of others 
which want the same. Now, the greatest commodities 
of mankind are the arts ; namely, of measuring matter 
and motion ; of moving ponderous bodies ; of architec- 
ture; of navigation; of making instruments for all 
uses ; of calculating the celestial motions, the aspects of 
the stars, and the parts of time; of geography, &c. 
By which sciences, how great benefits men receive is 
more easily understood than expressed. These bene- 
fits are enjoyed by almost all the people of Europe, by 
most of those of Asia, and by some of Africa : but the 
Americans, and they that live near the Poles, do totally 
want them. But why? Have they sharper wits than 
these? Have not all men one kind of soul, and the 
same faculties of mind? What, then, makes this dif- 
ference, except philosophy? Philosophy, therefore, is 
the cause of all these benefits. But the utility of moral 
and civil philosophy is to be estimated, not so much 
by the commodities we have by knowing these sciences, 
as by the calamities we receive from not knowing them. 
Now, all such calamities as may be avoided by human 
industry, arise from war, but chiefly from civil war; 
for from this proceed slaughter, solitude, and the want 
of all things. But the cause of war is not that men 
are willing to have it ; for the will has nothing for ob- 
ject but good, at least that which seemeth good. Nor 
is it from this, that men know not that the effects of 
war are evil ; for who is there that thinks not poverty 



12 CONCERNING BODY. 

and loss of life to be great evils? The cause, there- 
fore, of civil war is, that men know not the causes 
neither of war nor peace, there being but few in the 
world that have learned those duties which unite and 
keep men in peace, that is to say, that have learned the 
rules of civil life sufficiently. Now, the knowledge of 
these rules is moral philosophy. But why have they 
not learned them, unless for this reason, that none 
hitherto have taught them in a clear and exact method ? 
For what shall we say? Could the ancient masters of 
Greece, Egypt, Rome, and others, persuade the un- 
skilful multitude to their innumerable opinions con- 
cerning the nature of their gods, which they themselves 
know not whether they were true or false, and which 
were indeed manifestly false and absurd; and could 
they not persuade the same multitude to civil duty, if 
they themselves had understood it? Or shall those 
few writings of geometricians which are extant, be 
thought sufficient for the taking away of all contro- 
versy in the matters they treat of, and shall those in- 
numerable and huge volumes of ethics be thought 
unsufficient, if what they teach had been certain and 
well demonstrated? What, then, can be imagined to 
be the cause that the writings of those men have 
increased science, and the writings of these have in- 
creased nothing but words, saving that the former were 
written by men that knew, and the latter by such as 
know not, the doctrine they taught only for ostenta- 
tion of their wit and eloquence ? Nevertheless, I deny 
not but the reading of some such books is very delight- 
ful ; for they are most eloquently written, and contain 
many clear, wholesome and choice sentences, which yet 
are not universally true, though by them universally 
pronounced. From whence it comes to pass, that the 



OF PHILOSOPHY. 13 

circumstances of times, places, and persons being 
being changed, they are no less frequently made use of 
to confirm wicked men in their purposes, than to make 
them understand the precepts of civil duties. Now 
that which is chiefly wanting in them, is a true and cer- 
tain rule of our actions, by which we might know 
whether that we undertake be just or unjust. For it 
is to no purpose to be bidden in every thing to do right, 
before there be a certain rule and measure of right 
established, which no man hitherto hath established. 
Seeing, therefore, from the not knowing of civil duties, 
that is, from the want of moral science, proceed civil 
wars, and the greatest calamities of mankind, we may 
very well attribute to such science the production of 
the contrary commodities. And thus much is suffi- 
cient, to say nothing of the praises and other content- 
ment proceeding from philosophy, to let you see the 
utility of the same in every kind thereof. 

8. The subject of Philosophy, or the matter it treats 
of, is every body of which we can conceive any gen- 
eration, and which we may, by any consideration there- 
of, compare with other bodies, or which is capable of 
composition and resolution ; that is to say, every body 
of whose generation or properties we can have any 
knowledge. And this may be deduced from the defi- 
nition of philosophy, whose profession it is to search 
out the properties of bodies from their generation, or 
their generation from their properties; and, therefore, 
where there is no generation or property, there is no 
philosophy. Therefore it excludes Theology, I mean * 
the doctrine of God, eternal, ingenerable, incomprehen- # 
sible, and in whom there is nothing neither to divide * 
nor compound, nor any generation to be conceived. 

It excludes the doctrine of angels, and all such things I 



14 CONCERNING BODY. 

as are thought to be neither bodies nor properties of 
bodies ; there being in them no place neither for com- 
position nor division, nor any capacity of more and 
less, that is to say, no place for ratiocination. 

It excludes history, as well natural as political, 
though most useful (nay necessary) to philosophy; 
because such knowledge is but experience, or author- 
ity, and not ratiocination. 

It excludes all such knowledge as is acquired by Di- 
vine inspiration, or revelation, as not derived to us by 
reason, but by Divine grace in an instant, and, as it 
were, by some sense supernatural. 

It excludes not only all doctrines which are false, 
but such also as are not well-grounded ; for whatsoever 
we know by right ratiocination, can neither be false nor 
doubtful; and, therefore, astrology, as it is now held 
forth, and all such divinations rather than sciences, are 
excluded. 

Lastly, the doctrine of God's worship is excluded 
from philosophy, as being not to be known by natural 
reason, but by the authority of the Church; and as 
being the object of faith, and not of knowledge. 

9. The principal parts of philosophy are two. For 
two chief kinds of bodies, and very different from one 
another, offer themselves to such as search after their 
generation and properties ; one whereof being the work 
of nature, is called a natural body, the other is called a 
commonwealth, and is made by the wills and agree- 
ment of men. And from these spring the two parts of 
philosophy, called natural and civil. But seeing that, 
for the knowledge of the properties of a common- 
wealth, it is necessary first to know the dispositions, 
affections, and manners of men, civil philosophy is 
again commonly divided into two parts, whereof one, 



OF PHILOSOPHY. 15 

which treats of men's dispositions and manners, is 
called ethics; and the other, which takes cognizance of 
their civil duties, is called politics, or simply civil phi- 
losophy. In the first place, therefore (after I have set 
down such premises as appertain to the nature of 
philosophy in general), I will discourse of bodies nat- 
ural; in the second, of the dispositions and manners of 
men; and in the third, of the civil duties of subjects* 
10. To conclude; seeing there may be many who 
will not like this my definition of philosophy, and will 
say, that, from the liberty which a man may take of so 
defining as seems best to himself, he may conclude any 
thing from any thing (though I think it no hard matter 
to demonstrate that this definition of mine agrees with 
the sense of all men) ; yet, lest in this point there 
should be any cause of dispute betwixt me and them, 
I here undertake no more than to deliver the elements 
of that science by which the effects of anything may 
be found out from the known generation of the same, 
or contrarily, the generation from the effects ; to the 
end that they who search after other philosophy, may 
be admonished to seek it from other principles. 

CHAPTER II. 

OF NAMES. 

I. The necessity of sensible Moniments or Marks for the help 
of Memory : a Mark defined. — 2. The necessity of Marks for 
the signification of the conceptions of the Mind. — 3. Names 
supply both these necessities. — 4. The Definition of a Name. 
—5. Names are Signs not of Things, but of our Cogitations. 
— 6. What it is we give Names to. — 7. Names Positive and 



* For lists of the writings of Hobbes on ethics and on pol- 
itics, cf. p. xviii. 



16 CONCERNING BODY. 

Negative. — 8. Contradictory Names. — 9. A Common Name. 
— 10. Names of the First and Second Intention. — 11. Uni- 
versal, Particular, Individual, and Indefinite Names. — 12. 
Names Univocal and Equivocal. — 13. Absolute and Relative 
Names. — 14. Simple and Compounded Names. — 15. A Pre- 
dicament described. — 16. Some things to be noted concern- 
ing Predicaments. 

CHAPTER III. 

OF PROPOSITION. 

i. Divers kinds of speech. — 2. Proposition defined. — 3. Subject, 
predicate, and copula, what they are ; and abstract and con- 
crete what. The use and abuse of names abstract. — 5. 
Proposition, universal and particular. — 6. Affirmative and 
negative. — 7. True and false. — 8. True and false belongs to 
speech, and not to things. — 9. Proposition, primary, not pri- 
mary, definition, axiom, petition. — 10. Proposition, necessary 
and contingent. — II. Categorical and hypothetical. — 12. The 
same proposition diversely pronounced. — 13. Propositions 
that may be reduced to the same categorical proposition, are 
equipollent. — 14. Universal propositions converted by con- 
tradictory names, are equipollent. — 15. Negative propositions 
are the same, whether negation be before or after the copula. 
— 16. Particular propositions simply converted, are equipol- 
lent. — 17. What are subaltern, contrary, subcontrary, and 
contradictory propositions. — 18. Consequence, what it is. — 19. 
Falsity cannot follow from truth. — 20. How one proposition 
is the cause of another. 

CHAPTER IV. 

OF SYLLOGISM. 

I. The definition of syllogism. — 2. In a syllogism there are but 
three terms. — 3. Major, minor, and middle term; also major 
and minor proposition, what they are. — 4. The middle term 
in every syllogism ought to be determined in both the prop- 



OF PHILOSOPHY. 17 

ositions to one and the same thing. — 5. From two particular 
propositions nothing can be concluded. — 6. A syllogism is 
the collection of two propositions into one sum. — 7. The fig- 
ure of a syllogism, what it is. — 8. What is in the mind an- 
swering to a syllogism. — 9. The first indirect figure, how it 
is made. — 10. The second indirect figure, how made. — 11. 
How the third indirect figure is made. — 12. There are many 
moods in every figure, but most of them useless in philos- 
ophy. — 13. An hypothetical syllogism when equipollent to a 
categorical. 

CHAPTER V. 

OF ERRING, FALSITY, AND CAPTIONS. 

I. Erring and falsity, how they differ. Error of the mind by 
itself without the use of words, how it happens. — 2. A seven- 
fold incoherency of names, every one of which makes always 
a false proposition. — 3. Examples of the first manner of in- 
coherency. — 4. Of the second. — 5. Of the third. — 6. Of the 
fourth.— 7. Of the fifth.— 8. Of the sixth.— 9. Of the seventh. 
10. Falsity of propositions detected by resolving the terms 
with definitions continued till they come to simple names, or 
names that are the most general of their kind. — 11. Of the 
fault of a syllogism consisting of the implication of the terms 
with the copula. — 12. Of the fault which consists in equivo- 
cation. — 13. Sophistical captions are oftener faulty in the 
matter than in the form of syllogisms. 

CHAPTER VI. 

OF METHOD. 

I. Method and science defined. — 2. It is more easily known 
concerning singular, than universal things, that they are ; and 
contrarily, it is more easily known concerning universal, than 
singular things, why they are, or what are their causes. — 
3.What it is philosophers seek to know. — 4. The first part, 
by which principles are found out, is purely analytical. — 5. 
The highest causes, and most universal in every kind, are 



18 CONCERNING BODY. 

known by themselves. — 6. Method from principles found 
out, tending to science simply, what it is. — 7. That method 
of civil and natural science, which proceeds from sense to 
principles, is analytical; and again, that, which begins at 
principles, is synthetical. — 8. The method of searching out, 
whether any thing propounded be matter or accident. — 9. 
The method of seeking whether any accident be in this, or 
in that subject. — 10. The method of searching after the 
cause of any effect propounded. — II. Words serve to inven- 
tion, as marks; to demonstration, as signs. — 12. The method 
of demonstration is synthetical. — 13. Definitions only are pri- 
mary and universal propositions. — 14. The nature and defi- 
nition of a definition. — 15. The properties of a definition. — 
16. The nature of a demonstration. — 17. The properties of a 
demonstration, and order of things to be demonstrated. — 18. 
The faults of a demonstration. — 19. Why the analytical 
method of geometricians cannot be treated of in this place. 

I. For the understanding of method, it will be nec- 
essary for me to repeat the definition of philosophy, de- 
livered above (Chap. 1, art. 2.) in this manner, Philos- 
ophy is the knowledge we acquire, by true ratiocina- 
tion, of appearances, or apparent effects, from the 
knowledge we have of some possible production or 
generation of the same; and of such production, as has 
been or may be, from the knowledge we have of the 
effects. Method, therefore, in the study of philoso- 
phy, is the shortest way of -finding out effects by their 
known causes, or of causes by their known effects. 
But we are then said to know any effect, when we 
know that there be causes of the same, and in what 
subject those causes are, and in what subject they pro- 
duce that effect, and in what manner they work the 
same. And this is the science of causes, or, as they 
call it, of the fkori. All other science, which is called 
the on, is either perception by sense, or the imagina- 
tion, or memory remaining after such perception. 



OF METHOD. 19 

The first beginnings, therefore, of knowledge, are 
the phantasms of sense and imagination ; and that there 
be such phantasms we know well enough by nature; 
but to know why they be, or from what causes they 
proceed, is the work of ratiocination; which consists 
(as is said above, in the 1st Chapter, Art. 2) in com- 
position, and division or resolution. There is there- 
fore no method, by which we find out the causes of 
things, but is either compositive or resolutive, or partly 
compositive, and partly resolutive. And the resolutive 
is commonly called analytical method, as the composi- 
tive is called synthetical. 

2* It is common to all sorts of method, to proceed 
from known things to unknown ; and this is manifest 
from the cited definition of philosophy. But in knowl- 
edge by sense, the whole object is more known, than 
any part thereof; as when we see a man, the concep- 
tion or whole idea of that man is first or more known, 
than the particular ideas of his being Hgurate, animate, 
and rational; that is, we first see the whole man, and 
take notice of his being, before we observe in him 
those other particulars. And therefore in any knowl- 
edge of the on, or that any thing is, the beginning of 
our search is from the whole idea; and contrarily, in 
our knowledge of the otort, or of the causes of any 
thing, that is, in the sciences, we have more knowledge 
of the causes of the parts than of the whole. For the 
cause of the whole is compounded of the causes of the 
parts ; but it is necessary that we know the things that 
are to be compounded, before we can know the whole 
compound. Now, by parts, I do not here mean parts 
of the thing itself, but parts of its nature ; as, by the 
parts of man, I do not understand his head, his shoul- 



20 CONCERNING BODY. 

ders, his arms, &c. but his figure, quantity, motion, 
sense, reason, and the like ; which accidents being com- 
pounded or put together, constitute the whole nature 
of man, but not the man himself. And this is the 
meaning of that common saying, namely, that some 
things are more known to us, others more known to 
nature; for I do not think that they, which so distin- 
guish, mean that something is known to nature, which 
is known to no man; and therefore, by those things, 
that are more known to us, we are to understand things 
we take notice of by our senses, and, by more known to 
nature, those we acquire the knowledge of by reason; 
for in this sense it is, that the whole, that is, those 
things that have universal names, (which, for brevity's 
sake, I call universal) are more known to us than the 
parts, that is, such things as have names less universal, 
(which I therefore call singular) ; and the causes of 
the parts are more known to nature than the cause of 
the whole ; that is, universals than singulars. 

3. In the study of philosophy, men search after 
science either simply or indefinitely; that is, to know 
as much as they can, without propounding to them- 
selves any limited question; or they enquire into the 
cause of some determined appearance, or endeavour to 
find out the certainty of something in question, as what 
is the cause of light, of heat, of gravity, of a figure 
propounded, and the like ; or in what subject any pro- 
pounded accident is inherent; or what may conduce 
most to the generation of some propounded effect from 
many accidents; or in what manner particular causes 
ought to be compounded for the production of some 
certain effect. Now, according to this variety of 
things in question, sometimes the analytical method is 
to be used, and sometimes the synthetical. 



OF METHOD. 21 

4. But to those that search after science indefinitely, 
which consists in the knowledge of the causes of all 
things, as far forth as it may be attained, (and the 
causes of singular things are compounded of the causes 
of universal or simple things) it is necessary that they 
know the causes of universal things, or of such acci- 
dents as are common to all bodies, that is, to all matter, 
before they can know the causes of singular things, 
that is, of those accidents by which one thing is distin- 
guished from another. And, again, they must know 
what those universal things are, before they can know 
their causes. Moreover, seeing universal things are 
contained in the nature of singular things, the knowl- 
edge of them is to be acquired by reason, that is, by 
resolution. For example, if there be propounded a 
conception or idea of some singular thing, as of a 
square , this square is to be resolved into a plain, termi- 
nated with a certain number of equal and straight lines 
and right angles. For by this resolution we have these 
things universal or agreeable to all matter, namely, 
line, plain, (which contains superficies) terminated, 
angle, straightness, rectitude, and equality; and if we 
can find out the causes of these, we may compound 
them altogether into the cause of a square. Again, if 
any man propound to himself the conception of gold, 
he may, by resolving, come to the ideas of solid, visible, 
heavy, (that is, tending to the centre of the earth, or 
downwards) and many other more universal than 
gold itself; and these he may resolve again, till he 
come to such things as are most universal. And in 
this manner, by resolving continually, we may come to 
know what those things are, whose causes being first 
known severally, and afterwards compounded, bring 
us to the knowledge of singular things. I conclude, 



22 CONCERNING BODY. 

therefore, that the method of attaining to the universal 
knowledge of things, is purely analytical. 

5. But the causes of universal things (of those, at 
least, that have any cause) are manifest of themselves, 
or (as they say commonly) known to nature; so that 
they need no method at all; for they have all but one 
universal cause, which is motion. For the variety of 
all figures arises out of the variety of those motions by 
which they are made; and motion cannot be under- 
stood to have any other cause besides motion ; nor has 
the variety of those things we perceive by sense, as of 
colours, sounds, savours, &c. any other cause than mo- 
tion, residing partly in the objects that work upon our 
senses, and partly in ourselves, in such manner, as that 
it is manifestly some kind of motion, though we can- 
not, without ratiocination, come to know what kind. 
For though many cannot understand till it be in some 
sort demonstrated to them, that all mutation consists in 
motion ; yet this happens not from any obscurity in the 
thing itself, (for it is not intelligible that anything can 
depart either from rest, or from the motion it has, ex- 
cept by motion), but either by having their natural dis- 
course corrupted with former opinions received from 
their masters, or else for this, that they do not at all 
bend their mind to the enquiring out of truth. 

6. By the knowledge therefore of universals, and 
of their causes (which are the first principles by which 
we know the S«m of things) we have in the first place 
their definitions, (which are nothing but the explica- 
tion of our simple conceptions.) For example, he that 
has a true conception of place, cannot be ignorant of 
this definition, place is that space which is possessed or 
filled adequately by some body; and so, he that con- 
ceives motion aright, cannot but know that motion is 






OF METHOD. 23 

the privation of one place, and the acquisition of an- 
other. In the next place, we have their generations or 
descriptions; as (for example) that a line is made by 
the motion of a point, superficies by the motion of a 
line, and one motion by another motion, &c. It re- 
mains, that we enquire what motion begets such and 
such effects ; as, what motion makes a straight line, 
and what a circular ; what motion thrusts, what draws, 
and by what way; what makes a thing which is seen 
or heard, to be seen or heard sometimes in one manner, 
sometimes in another. Now the method of this kind 
of enquiry, is compositive. For first, we are to observe 
what effect a body moved produceth, when we con- 
sider nothing in it besides its motion ; and we see pres- 
ently that this makes a line, or length ; next, what the 
motion of a long body produces, which we find to be 
superficies; and so forwards, till we see what the ef- 
fects of simple motion are; and then, in like manner, 
we are to observe what proceeds from the addition, 
multiplication, substraction, and division, of these mo- 
tions, and what effects, what figures, and what prop- 
erties, they produce; from which kind of contempla- 
tion sprung that part of philosophy which is called 
geometry. 

From this consideration of what is produced by 
simple motion, we are to pass to the consideration 
of what effects one body moved worketh upon another ; 
and because there may be motion in all the several 
parts of a body, yet so as that the whole body remain 
still in the same place, we must enquire first, what 
motion causeth such and such motion in the whole, that 
is, when one body invades another body which is either 
at rest or in motion, what way, and with what swift- 
ness, the invaded body shall move; and, again, what 



24 CONCERNING BODY. 

motion this second body will generate in a third, and 
so forwards. From which contemplation shall be 
drawn that part of philosophy which treats of motion. 

In the third place we must proceed to the enquiry of 
such effects as are made by the motion of the parts of 
any body, as, how it comes to pass, that things when 
they are the same, yet seem not to be the same, but 
changed. And here the things we search after are 
sensible qualities, such as light, colour, transparency, 
opacity, sound, odour, savour, heat, cold, and the like ; 
which because they cannot be known till we know the 
causes of sense itself, therefore the consideration of 
the causes of seeing, hearing, smelling, tasting and 
touching, belongs to this third place; and all those 
qualities and changes, above mentioned, are to be re- 
ferred to the fourth place; which two considerations 
comprehend that part of philosophy which is called 
physics. And in these four parts is contained whatso- 
ever in natural philosophy may be explicated by dem- 
onstration, properly so called. For if a cause were to 
be rendered of natural appearances in special, as, what 
are the motions and influences of the heavenly bodies, 
and of their parts, the reason hereof must either be 
drawn from the parts of the sciences above mentioned, 
or no reason at all will be given, but all left to uncer- 
tain conjecture. 

After physics we must come to moral philosophy; in 
which we are to consider the motions of the mind, 
namely, appetite, aversion, love, benevolence, hope, 
fear, anger, emulation, envy, &c. ; what causes they 
have, and of what they be causes. And the reason why 
these are to be considered after physics is, that they 
have their causes in sense and imagination, which are 
the subject of physical contemplation. Also the reason, 



OF METHOD. 25 

why all these things are to be searched after in the 
order above-said, is, that physics cannot be understood, 
except we know first what motions are in the smallest 
parts of bodies ; nor such motion of parts, till we know 
what it is that makes another body move ; nor this, till 
we know what simple motion will effect. And because 
all appearance of things to sense is determined, and 
made to be of such and such quality and quantity by 
compounded motions, every one of which has a certain 
degree of velocity, and a certain and determined way ; 
therefore, in the first place, we are to search out the 
ways of motion simply (in which geometry consists) ; 
next the ways of such generated motions as are mani- 
fest ; and, lastly, the ways of internal and invisible mo- 
tions (which is the enquiry of natural philosophers). 
And, therefore, they that study natural philosophy, 
study in vain, except they begin at geometry ; and such 
writers or disputers thereof, as are ignorant of geom- 
etry, do but make their readers and hearers lose their 
time. 

7. Civil and moral philosophy do not so adhere 
to one another, but that they may be severed. For the 
causes of the motions of the mind are known, not only 
by ratiocination, but also by the experience of every 
man that takes the pains to observe those motions 
within himself. And, therefore, not only they that 
have attained the knowledge of the passions and per- 
turbations of the mind, by the synthetical method, and 
from the very first principles of philosophy, may by 
proceeding in the same way, come to the causes and 
necessity of constituting commonwealths, and to get 
the knowledge of what is natural right, and what are 
civil duties; and, in every kind of government, what 
are the rights of the commonwealth, and all other 



26 CONCERNING BODY. 

knowledge appertaining to civil philosophy; for this 
reason, that the principles of the politics consist in the 
knowledge of the motions of the mind, and the knowl- 
edge of these motions from the knowledge of sense and 
imagination; but even they also that have not learned 
the first part of philosophy, namely, geometry and 
physics, may, notwithstanding, attain the principles 
of civil philosophy, by the analytical method. For 
if a question be propounded, as, whether such an 
action be just or unjust; if that unjust be resolved into 
fact against law, and that notion law into the command 
of him or them that have coercive power; and that 
power be derived from the wills of men that constitute 
such power, to the end they may live in peace, they 
may at last come to this, that the appetites of men and 
the passions of their minds are such, that, unless they 
be restrained by some power, they will always be 
making war upon one another; which may be known 
to be so by any man's experience, that will but examine 
his own mind. And, therefore, from hence he may 
proceed, by compounding, to the determination of the 
justice or injustice of any propounded action. So that 
it is manifest, by what has been said, that the method 
of philosophy, to such as seek science simply, without 
propounding to themselves the solution of any particu- 
lar question, is partly analytical, and partly synthetical ; 
namely, that which proceeds from sense to the invention 
Of principles, analytical ; and the rest synthetical. 

8. To those that seek the cause of some certain and 
propounded appearance or effect, it happens, some- 
times, that they know not whether the thing, whose 
cause is sought after, be matter or body, or some acci- 
dent of a body. For though in geometry, when the 
cause is sought of magnitude, or proportion, or figure, 



OF METHOD. 27 

it be certainly known that these things, namely magni- 
tude, proportion, and figure, are accidents; yet in 
natural philosophy, where all questions are concerning 
the causes of the phantasms of sensible things, it is not 
so easy to discern between the things themselves, from 
which those phantasms proceed, and the appearances of 
those things to the sense; which have deceived many, 
especially when the phantasms have been made by 
light. For example, a man that looks upon the sun, 
has a certain shining idea of the magnitude of about a 
foot over, and this he calls the sun, though he know 
the sun to be truly a great deal bigger; and, in like 
manner, the phantasm of the same thing appears some- 
times round, by being seen afar off, and sometimes 
square, by being nearer. Whereupon it may well be 
doubted, whether that phantasm be matter, or some 
body natural, or only some accident of a body ; in the 
examination of which doubt we may use this method. 
The properties of matter and accidents already found 
out by us, by the synthetical method, from their defini- 
tions, are to be compared with the idea we have before 
us; and if it agree with the properties of matter or 
body, then it is a body; otherwise it is an accident. 
Seeing, therefore, matter cannot by any endeavor of 
ours be either made or destroyed, or increased, or di- 
minished, or moved out of its place, whereas that idea 
appears, vanishes, is increased and diminished, and 
moved hither and thither at pleasure ; we may certainly 
conclude that it is not a body, but an accident only. And 
this method is synthetical. 

9. But if there be a doubt made concerning the sub- 
ject of any known accident (for this may be doubted 
sometimes, as in the precedent example, doubt may be 
made in what subject that splendour and apparent 



28 CONCERNING BODY. 

magnitude of the sun is), then our enquiry must pro- 
ceed in this manner. First, matter in general must be 
divided into parts, as, into object, medium, and the 
sentient itself, or such other parts as seem most con- 
formable to the thing propounded. Next, these parts 
are severally to be examined how they agree with the 
definition of the subject; and such of them as are not 
capable of that accident are to be rejected. For ex- 
ample, if by any true ratiocination the sun be found 
to be greater than its apparent magnitude, then that 
magnitude is not in the sun; if the sun be in one 
determined straight line, and one determined distance, 
and the magnitude and splendour be seen in more lines 
and distances than one, as it is in reflection or refrac- 
tion, then neither that splendour nor apparent magni- 
tude are in the sun itself, and, therefore, the body of the 
sun cannot be the subject of that splendour and magni- 
tude. And for the same reasons the air and other parts 
will be rejected, till at last nothing remain which can be 
the subject of that splendour and magnitude but the 
sentient itself. And this method, in regard the subject 
is divided into parts, is analytical; and in regard the 
properties, both of the subject and accident, are com- 
pared with the accident concerning whose subject the 
enquiry is made, it is synthetical. 

10. But when we seek after the cause of any pro- 
pounded effect, we must in the first place get into our 
mind an exact notion or idea of that which we call 
cause, namely, that a cause is the sum or aggregate of 
all such accidents, both in the agents and the patient, 
as concur to the producing of the effect propounded; 
all of which existing together, it cannot be understood 
but that the effect existeth with them; or that it can 
possibly exist if any one of them be absent. This being 



OF METHOD. 29 

known, in the next place we must examine singly every 
accident that accompanies or precedes the effect, as far 
forth as it seems to conduce in any manner to the pro- 
duction of the same, and see whether the propounded 
effect may be conceived to exist, without the existence 
of any of those accidents ; and by this means separate 
such accidents, as do not concur, from such as concur 
to produce the said effect ; which being done, we are to 
put together the concurring accidents, and consider 
whether we can possibly conceive, that when these are 
all present, the effect propounded will not follow ; and 
if it be evident that the effect will follow, then that 
aggregate of accidents is the entire cause, otherwise 
not ; but we must still search out and put together other 
accidents. For example, if the cause of light be pro- 
pounded to be sought out; first, we examine things 
without us, and find that whensoever light appears, 
there is some principal object, as it were the fountain 
of light, without which we cannot have any perception 
of light ; and, therefore, the concurrence of that object 
is necessary to the generation of light. Next we con- 
sider the medium, and find, that unless it be disposed 
in a certain manner, namely, that it be transparent, 
though the object remain the same, yet the effect will 
not follow; and, therefore, the concurrence of trans- 
parency is also necessary to the generation of light. 
Thirdly, we observe our own body, and find that by 
the indisposition of the eyes, the brain, the nerves, and 
the heart, that is, by obstructions, stupidity, and de- 
bility we are deprived of light, so that a fitting disposi- 
tion of the organs to receive impressions from without 
is likewise a necessary part of the cause of light. 
Again, of all the accidents inherent in the object, there 
is none that can conduce to the effecting of light, but 



30 CONCERNING BODY. 

only action (or a certain motion), which cannot be 
conceived to be wanting, whensoever the effect is 
present ; for, that anything may shine, it is not requisite 
that it be of such or such magnitude or figure, or that 
the whole body of it be moved out of the place it is in 
(unless it may perhaps be said, that in the sun, or other 
body, that which causes light is the light it hath in 
itself; which yet is but a trifling exception, seeing 
nothing is meant thereby but the cause of light; as 
if any man should say that the cause of light is 
that in the sun which produceth it) ; it remains, 
therefore, that the action, by which light is gen- 
erated, is motion only in the parts of the object. Which 
being understood, we may easily conceive what it is the 
medium contributes, namely, the continuation of that 
motion to the eye; and, lastly, what the eye and the 
rest of the organs of the sentient contribute, namely, 
the continuation of the same motion to the last organ 
of sense, the heart. And in this manner the cause of 
light may be made up of motion continued from the 
original of the same motion, to the original of vital 
motion, light being nothing but the alteration of vital 
motion, made by the impression upon it of motion 
continued from the object. But I give this only for an 
example, for I shall speak more at large of light, and 
the generation of it, in its proper place. In the mean 
time it is manifest, that in the searching out of causes, 
there is need partly of the analytical, and partly of the 
synthetical method ; of the analytical, to conceive how 
circumstances conduce severally to the production of 
effects ; and of the synthetical, for the adding together 
and compounding of what they can effect singly by 
themselves. And thus much may serve for the method 
of invention. It remains that I speak of the method 



OF METHOD. 31 

of teaching, that is, of demonstration, and of the means 
by which we demonstrate. 

11. In the method of invention, the use of words 
consists in this, that they may serve for marks, by 
which, whatsoever we have found out may be recalled 
to memory; for without this all our inventions perish, 
nor will it be possible for us to go on from principles 
beyond a syllogism or two, by reason of the weakness 
of memory. For example, if any man, by considering 
a triangle set before him, should find that all its angles 
together taken are equal to two right angles, and that 
by thinking of the same tacitly, without any use of 
words either understood or expressed ; and it should 
happen afterwards that another triangle, unlike the 
former, or the same in different situation, should be 
offered to his consideration, he would not know readily 
whether the same property were in this last or no, but 
would be forced, as often as a different triangle were 
brought before him (and the difference of triangles is 
infinite) to begin his contemplation anew; which he 
would have no need to do if he had the use of names, 
for every universal name denotes the conceptions we 
have of infinite singular things. Nevertheless, as I said 
above, they serve as marks for the help of our memory, 
whereby we register to ourselves our own inventions; 
but not as signs by which we declare the same to 
others; so that a man may be a philosopher alone by 
himself, without any master; Adam had this capacity. 
But to teach, that is, to demonstrate, supposes two at 
the least, and syllogistical speech. 

12. And seeing teaching is nothing but leading 
the mind of him we teach, to the knowledge of our in- 
ventions, in that track by which we attained the same 
with our own mind; therefore, the same method that 



32 CONCERNING BODY. 

served for our invention, will serve also for demon- 
stration to others, saving that we omit the first part of 
method which proceeded from the sense of things to 
universal principles, which, because they are principles, 
cannot be demonstrated; and seeing they are known 
by nature, (as was said above in the 5th article) they 
need no demonstration, though they need explication. 
The whole method, therefore, of demonstration, is 
synthetical, consisting of that order of speech which 
begins from primary or most universal propositions, 
which are manifest of themselves, and proceeds by a 
perpetual composition of propositions into syllogisms, 
till at last the learner understand the truth of the con- 
clusion sought after. 

13. Now, such principles are nothing but defi- 
nitions, whereof there are two sorts; one of names, 
that signify such things as have some conceivable 
cause, and another of such names as signify things of 
which we can conceive no cause at all. Names of the 
former kind are, body, or matter, quantity, or exten- 
sion, motion, and whatsoever is common to all matter. 
Of the second kind, are such a body, such and so great 
motion, so great magnitude, such figure, and whatso- 
ever we can distinguish one body from another by. 
And names of the former kind are well enough defined, 
when, by speech as short as may be, we raise in the 
mind of the hearer perfect and clear ideas or concep- 
tions of the things named, as when we define motion 
to be the leaving of one place, and the acquiring of 
another continually; for though no thing moved, nor 
any cause of motion be in that definition, yet, at the 
hearing of that speech, there will come into the mind 
of the hearer an idea of motion clear enough. But 
definitions of things, which may be understood to have 



OF METHOD. 33 

some cause, must consist of such names as express the 
cause or manner of their generation, as when we define 
a circle to be a figure made by the circumduction of a 
straight line in a plane, &c. Besides definitions, there 
is no other proposition that ought to be called primary, 
or (according to severe truth) be received into the 
number of principles. For those axioms of Euclid, 
seeing they may be demonstrated, are no principles of 
demonstration, though they have by the consent of all 
men gotten the authority of principles, because they 
need not be demonstrated. Also, those petitions, or 
postulata, (as they call them) though they be princi- 
ples, yet they are not principles of demonstration, but 
of construction only; that is, not of science, but of 
power; or (which is all one) not of theorems, which 
are speculations, but of problems, which belong to prac- 
tice, or the doing of something. But as for those com- 
mon received opinions, Nature abhors vacuity, Nature 
doth nothing in vain, and the like, which are neither 
evident in themselves, nor at all to be demonstrated, 
and which are oftener false than true, they are much 
less to be acknowledged for principles. 

To return, therefore, to definitions; the reason why 
I say that the cause and generation of such things, as 
have any cause or generation, ought to enter into their 
definitions, is this. The end of science is the demon- 
stration of the causes and generation of things ; which 
if they be not in the definitions, they cannot be found 
in the conclusion of the first syllogism, that is made 
from those definitions; and if they be not in the first 
conclusion, they will not be found in any further con- 
clusion deduced from that ; and, therefore, by proceed- 
ing in this manner, we shall never come to science; 



34 CONCERNING BODY. 

which is against the scope and intention of demonstra- 
tion. 

14. Now, seeing definitions (as I have said) are 
principles, or primary propositions, they are therefore 
speeches ; and seeing they are used for the raising of an 
idea of some thing in the mind of the learner, whenso- 
ever that thing has a name, the definition of it can be 
nothing but the explication of that name by speech; 
and if that name be given it for some compounded con- 
ception, the definition is nothing but a resolution of 
that name into its most universal parts. As when we 
define man, saying man is a body animated, sentient, 
rational, those names, body animated, &c, are parts of 
that whole name man; so that definitions of this kind 
always consist of genus and difference; the former 
names being all, till the last, general; and the last of 
all, difference. But if any name be the most universal 
in its kind, then the definition of it cannot consist of 
genus and difference, but is to be made by such circum- 
locution, as best explicateth the force of that name. 
Again, it is possible, and happens often, that the genus 
and difference are put together, and yet make no defini- 
tion ; as these words, a straight line, contain both the 
genus and difference; but are not a definition, unless 
we should think a straight line may be thus defined, a 
straight line is a straight line: and yet if there were 
added another name, consisting of different words, but 
signifying the same thing which these signify, then 
these might be the definition of that name. From what 
has been said, it may be understood how a definition 
ought to be defined, namely, that it is a proposition, 
whose predicate resolves the subject, when it may; and 
when it may not, it exemplifies the same. 

15. The properties of a definition are: 



OF METHOD. 35 

First, that it takes away equivocation, as also all that 
multitude of distinctions, which are used by such as 
think they may learn philosophy by disputation. For 
the nature of a definition is to define, that is, to deter- 
mine the signification of the defined name, and to pare 
from it all other signification besides what is contained 
in the definition itself; and therefore one definition 
does as much, as all the distinctions (how many so- 
ever) that can be used about the name defined. 

Secondly, that it gives an universal notion of the 
thing defined, representing a certain universal picture 
thereof, not to the eye, but to the mind. For as when 
one paints a man, he paints the image of some man; 
so he, that defines the name man, makes a representa- 
tion of some man to the mind. 

Thirdly, that it is not necessary to dispute whether 
definitions are to be admitted or no. For when a 
master is instructing his scholar, if the scholar under- 
stand all the parts of the thing defined, which are re- 
solved in the definition, and yet will not admit of the 
definition, there needs no further controversy betwixt 
them, it being all one as if he refused to be taught. 
But if he understand nothing, then certainly the defi- 
nition is faulty; for the nature of a definition consists 
in this, that it exhibit a clear idea of the thing defined ; 
and principles are either known by themselves, or else 
they are not principles. 

Fourthly, that, in philosophy, definitions are before 
defined names. For in teaching philosophy, the first 
beginning is from definitions; and all progression in 
the same, till we come to the knowledge of the thing 
compounded, is compositive. Seeing, therefore, defi- 
nition is the explication of a compounded name by 
resolution, and the progression is from the parts to the 



36 CONCERNING BODY. 

compound, definitions must be understood before com- 
pounded names ; nay, when the names of the parts of 
any speech be explicated, it is not necessary that the 
definition should be a name compounded of them. For 
example, when these names, equilateral, quadrilateral, 
right-angled, are sufficiently understood, it is not neces- 
sary in geometry that there should be at all such a 
name as square; for defined names are received in 
philosophy for brevity's sake only. 

Fifthly, that compounded names, which are defined 
one way in some one part of philosophy, may in an- 
other part of the same be otherwise defined ; as a para- 
bola and an hyperbole have one definition in geometry, 
and another in rhetoric; for definitions are instituted 
and serve for the understanding of the doctrine 
which is treated of. And, therefore, as in one part of 
philosophy, a definition may have in it some one fit 
name for the more brief explanation of some proposi- 
tion in geometry; so it may have the same liberty in 
other parts of philosophy ; for the use of names is par- 
ticular (even where many agree to the settling of 
them) and arbitrary. 

Sixthly, that no name can be defined by any one 
word ; because no one word is sufficient for the resolv- 
ing of one or more words. 

Seventhly, that a defined name ought not to be re- 
peated in the definition. For a defined name is the 
whole compound, and a definition is the resolution of 
that compound into parts ; but no total can be part of 
itself. 

16. Any two definitions, that may be compounded 
into a syllogism, produce a conclusion ; which, because 
it is derived from principles, that is, from definitions, is 
said to be demonstrated; and the derivation or com- 



OF METHOD. 37 

position itself is called a demonstration. In like man- 
ner, if a syllogism be made of two propositions, whereof 
one is a definition, the other a demonstrated conclusion, 
or neither of them is a definition, but both formerly 
demonstrated, that syllogism is also called a demon- 
stration, and so successively. The definition therefore 
of a demonstration is this, a demonstration is a syllo- 
gism, or series of syllogisms, derived and continued, 
from the deiinitions of names, to the last conclusion. 
And from hence it may be understood, that all true 
ratiocination, which taketh its beginning from true 
principles, produceth science, and is true demonstra- 
tion. For as for the original of the name, although 
that, which the Greeks called diroSa&s, and the 
Latins demonstratio, was understood by them for that 
sort only of ratiocination, in which, by the describing 
of certain lines and figures, they placed the thing they 
were to prove, as it were before men's eyes, which is 
properly airoScucvvew , or to shew by the figure; yet 
they seem to have done it for this reason, that unless 
it were in geometry, (in which only there is place for 
such figures) there was no ratiocination certain, and 
ending in science, their doctrines concerning all other 
things being nothing but controversy and clamour; 
which, nevertheless, happened, not because the truth to 
which they pretended could not be made evident with- 
out figures, but because they wanted true principles, 
from which they might derive their ratiocination ; and, 
therefore, there is no reason but that if true definitions 
were premised in all sorts of doctrines, the demonstra- 
tions also would be trne. 

17. It is proper to methodical demonstration, 
First, that there be a true succession of one reason to 



38 CONCERNING BODY. 

another, according to the rules of syllogizing delivered 
above. 

Secondly, that the premises of all syllogisms be 
demonstrated from the first definitions. 

Thirdly, that after definitions, he that teaches or 
demonstrates any thing, proceed in the same method 
by which he found it out ; namely, that in the first place 
those things be demonstrated, which immediately suc- 
ceed to universal definitions (in which is contained that 
part of philosophy which is called philosophia prima). 
Next, those things which may be demonstrated by 
simple motion (in which geometry consists). After 
geometry, such things as may be taught or shewed by 
manifest action, that is, by thrusting from, or pulling 
towards. And after these, the motion or mutation of 
the invisible parts of things, and the doctrine of sense 
and imaginations, and of the internal passions, espe- 
cially those of men, in which are comprehended the 
grounds of civil duties, or civil philosophy; which 
takes up the last place. And that this method ought 
to be kept in all sorts of philosophy, is evident from 
hence, that such things as I have said are to be taught 
last, cannot be demonstrated, till such as are pro- 
pounded to be first treated of, be fully understood. Of 
which method no other example can be given, but that 
treatise of the elements of philosophy, which I shall 
begin in the next chapter, and continue to the end of 
the work. 

1 8. Besides those paralogisms, whose fault lies 
either in the falsity of the premises, or the want of true 
composition, of which I have spoken in the precedent 
chapter, there are two more, which are frequent in 
demonstration ; one whereof is commonly called petitio 
principii; the other is the supposing of a false cause; 



OF METHOD. 39 

and these do not only deceive unskilful learners, but 
sometimes masters themselves, by making them take 
that for well demonstrated, which is not demonstrated 
at all. Petitio principii is, when the conclusion to be 
proved is disguised in other words, and put for the 
definition or principle from whence it is to be demon- 
strated ; and thus, by putting for the cause of the thing 
sought, either the thing itself or some effect of it, they 
make a circle in their demonstration. As for example, 
he that would demonstrate that the earth stands still in 
the centre of the world, and should suppose the earth's 
gravity to be the cause thereof, and define gravity to 
be a quality by which every heavy body tends towards 
the centre of the world, would lose his labour ; for the 
question is, what is the cause of that quality in the 
earth? and, therefore, he that supposes gravity to be 
the cause, puts the thing itself for its own cause. 

Of a false cause I find this example in a certain 
treatise where the thing to be demonstrated is the 
motion of the earth. He begins, therefore, with this, 
that seeing the earth and the sun are not always in the 
same situation, it must needs be that one of them be 
locally moved, which is true ; next, he affirms that the 
vapours which the sun raises from the earth and sea, 
are, by reason of this motion, necessarily moved, which 
also is true ; from whence he infers the winds are made, 
and this may pass for granted ; and by these winds he 
says, the waters of the sea are moved, and by their 
motion the bottom of the sea, as if it were beaten for- 
wards, moves round; and let this also be granted; 
wherefore, he concludes, the earth is moved ; which is, 
nevertheless, a paralogism. For, if that wind were the 
cause why the earth was, from the beginning, moved 
round, and the motion either of the sun or the earth 



40 CONCERNING BODY. 

were the cause of that wind, then the motion of the 
sun or the earth was before the wind itself ; and if the 
earth were moved, before the wind was made, then 
the wind could not be the cause of the earth's revolu- 
tion; but, if the sun were moved, and the earth stand 
still, then it is manifest the earth might remain un- 
moved, notwithstanding that wind; and therefore that 
motion was not made by the cause which he allegeth. 
But paralogisms of this kind are very frequent among 
the writers of physics, though none can be more elabo- 
rate than this in the example given. 

19. It may to some men seem pertinent to treat in 
this place of that art of the geometricians, which they 
call logistica, that is, the art, by which, from supposing 
the thing in question to be true, they proceed by ratioci- 
nation, till either they come to something known, by 
which they may demonstrate the truth of the thing 
sought for ; or to something which is impossible, from 
whence they collect that to be false, which they sup- 
posed true. But this art cannot be explicated here, for 
this reason, that the method of it can neither be prac- 
tised, nor understood, unless by such as are well versed 
in geometry; and among geometricians themselves, 
they, that have most theorems in readiness, are the 
most ready in the use of this logistica; so that, indeed, 
it is not a distinct thing for geometry itself ; for there 
are, in the method of it, three parts ; the first whereof 
consists in the finding out of equality betwixt known 
and unknown things, which they call equation ; and this 
equation cannot be found out, but by such as know 
perfectly the nature, properties, and transpositions of 
proportion, as also the addition, subtraction, multiplica- 
tion, and division of lines and superficies, and the ex- 
traction of roots ; which are the parts of no mean geo- 



OF METHOD. 41 

metrician. The second is, when an equation is found, 
to be able to judge whether the truth or falsity of the 
question may be deduced from it, or no ; which yet re- 
quires greater knowledge. And the third is, when 
such an equation is found, as is fit for the solution of 
the question, to know how to resolve the same in such 
manner, that the truth or falsity may thereby mani- 
festly appear ; which, in hard questions, cannot be done 
without the knowledge of the nature of crooked-lined 
figures ; but he that understands readily the nature and 
properties of these, is a complete geometrician. It 
happens besides, that for the finding out of equations, 
there is no certain method, but he is best able to do it, 
that has the best natural wit. 



PART II. 

THE FIRST GROUNDS OF 
PHILOSOPHY. 

CHAPTER VII.* 

OF PLACE AND TIME. 

I. Things that have no existence, may nevertheless be under- 
stood and computed. — 2. What is Space. — 3. Time. — 4. Part. 
5. Division. — 6. One. — 7. Number. — 8. Composition. — 
9. The whole. — 10. Spaces and times contiguous, and con- 
tinual. — 11 Beginning, end, way, finite, infinite. — 12. What 
is infinite in power. Nothing infinite can be truly said to be 
either whole, or one; nor infinite spaces or times, many. — 
13. Division proceeds not to the least. 

I. In the teaching of natural philosophy, I cannot 
begin better (as I have already shewn) than from 
privation; that is, from feigning the world to be anni- 
hilated. But, if such annihilation of all things be sup- 
posed, it may perhaps be asked, what would remain for 
any man (whom only I except from this universal anni- 
hilation of things) to consider as the subject of 
philosophy, or at all to reason upon; or what to give 
names unto for ratiocination's sake. 

I say, therefore, there would remain to that man 



*For parallel passages from the Latin text of chapters 
VII.-X. of De Corpore, cf. pp. 183 seq. 

43 



44 CONCERNING BODY. 

ideas of the world, and of all such bodies as he had, 
before their annihilation, seen with his eyes, or per- 
ceived by any other sense; that is to say, the memory 
and imagination of magnitudes, motions, sounds, 
colours, &c. as also of their order and parts. All 
which things, though they be nothing but ideas and 
phantasms, happening internally to him that imagineth ; 
yet they will appear as if they were external, and not 
at all depending upon any power of the mind. And 
these are the things to which he would give names, 
and subtract them from, and compound them with one 
another. For seeing, that after the destruction of all 
other things, I suppose man still remaining, and namely 
that he thinks, imagines, and remembers, there can be 
nothing for him to think of but what is past; nay, if 
we do but observe diligently what it is we do when we 
consider and reason, we shall find, that though all 
things be still remaining in the world, yet we compute 
nothing but our own phantasms. For when we cal- 
culate the magnitude and motions of heaven or earth, 
we do not ascend into heaven that we may divide it 
into parts, or measure the motions thereof, but we do it 
sitting still in our closets or in the dark. Now things 
may be considered, that is, be brought into account, 
either as internal accidents of our mind, in which man- 
ner we consider them when the question is about some 
faculty of the mind; or as species of external things, 
not as really existing, but appearing only to exist, or 
to have a being without us. And in this manner we 
are now to consider them. 

2. If therefore we remember, or have a phantasm 
of any thing that was in the world before the supposed 
annihilation of the same; and consider, not that the 
thing was such or such, but only that it had a being 



OF PLACE AND TIME. 45 

without the mind, we have presently a conception of 
that we call space: an imaginary space indeed, because 
a mere phantasm, yet that very thing which all men call 
so. For no man calls it space for being already filled, 
but because it may be filled; nor does any man think 
bodies carry their places away with them, but that the 
same space contains sometimes one, sometimes another 
body; which could not be if space should always ac- 
company the body which is once in it. And this is of 
itself so manifest, that I should not think it needed any 
explaining at all, but that I find space to be falsely 
defined by certain philosophers, who infer from thence, 
one, that the world is infinite (for taking space to be 
the extension of bodies, and thinking extension may 
encrease continually, he infers that bodies may be in- 
finitely extended) ; and, another, from the same defi- 
nition, concludes rashly, that it is impossible even to 
God himself to create more worlds than one; for, if 
another world were to be created, he says, that seeing 
there is nothing without this world, and therefore (ac- 
cording to his definition) no space, that new world 
must be placed in nothing ; but in nothing nothing can 
be placed ; which he affirms only, without showing any 
reason for the same ; whereas the contrary is the truth : 
for more cannot be put into a place already filled, so 
much is empty space fitter than that, which is full, for 
the receiving of new bodies. Having therefore spoken 
thus much for these men's sakes, and for theirs that 
assent to them, I return to my purpose, and define space 
thus : Space is the phantasm of a thing existing with- 
out the mind simply; that is to say, that phantasm, in 
which we consider no other accident, but only that it 
appears without us. 
3. As a body leaves a phantasm of its magnitude in 



46 CONCERNING BODY. 

the mind, so also a moved body leaves a phantasm of its 
motion, namely, an idea of that body passing out of one 
space into another by continual succession. And this 
idea, or phantasm, is that, which (without receding 
much from the common opinion, or from Aristotle's 
definition) I call Time. For seeing all men confess a 
year to be time, and yet do not think a year to be the 
accident or affection of any body, they must needs con- 
fess it to be, not in the things without us, but only in the 
thought of the mind. So when they speak of the times 
of their predecessors, they do not think after their 
predecessors are gone, that their times can be any 
where else than in the memory of those that remember 
them. And as for those that say, days, years, and 
months are the motions of the sun and moon, see- 
ing it is all one to say, motion past and motion de- 
stroyed, and that future motion is the same with 
motion which is not yet begun, they say that, which 
they do not mean, that there neither is, nor has been, 
nor shall be any time : for of whatsoever it may be said, 
it has been or it shall be, of the same also it might have 
been said heretofore, or may be said hereafter, it is. 
What then can days, months, and years, be, but the 
names of such computations made in our mind ? Time 
therefore is a phantasm, but a phantasm of motion, for 
if we would know by what moments time passes away, 
we make use of some motion or other, as of the sun, of 
a clock, of the sand in an hourglass, or we mark some 
line upon which we imagine something to be moved, 
there being no other means by which we can take 
notice of any time at all. And yet, when I say time is 
a phantasm of motion, I do not say this is sufficient to 
define it by ; for this word time comprehends the notion 
of former and latter, or of succession in the motion of 



OF PLACE AND TIME. 47 

a body, in as much as it is first here then there. 
Wherefore a complete definition of time is such 
as this, time is the phantasm of before and after in 
motion; which agrees with this definition of Aristotle, 
time is the number of motion according to former and 
latter; for that numbering is an act of the mind; and 
therefore it is all one to say, time is the number of mo- 
tion according to former and latter; and time is a phan- 
tasm of motion numbered. But that other definition, 
time is the measure of motion, is not so exact, for we 
measure time by motion and not motion by time. 

4. One space is called part of another space, and 
one time part of another time, when this contains that 
and something besides. From whence it may be col- 
lected, that nothing can rightly be called a part, but 
that which is compared with something that contains it. 

5. And therefore to make parts, or to part or 
divide space or time, is nothing else but to consider 
one and another within the same; so that if any man 
divide space or time, the diverse conceptions he has 
are more, by one, than the parts he makes ; for his first 
conception is of that which is to be divided, then of 
some part of it, and again of some other part of it, and 
so forwards as long as he goes on in dividing. 

But it is to be noted, that here, by division, I do not 
mean the severing or pulling asunder of one space or 
time from another (for does any man think that one 
hemisphere may be separated from the other hemi- 
sphere, or the first hour from the second?) but diver- 
sity of consideration; so that division is not made by 
the operation of the hands but of the mind. 

6. When space or time is considered among other 
spaces or times, it is said to be one, namely, one of 
them; for except one space might be added to another, 



48 CONCERNING BODY. 

and subtracted from another space, and so of time, it 
would be sufficient to say space or time simply, and 
superfluous to say one space or one time, if it could not 
be conceived that there were another. The common 
definition of one, namely, that one is that which is un- 
divided, is obnoxious to an absurd consequence ; for it 
may thence be inferred, that whatsoever is divided is 
many things, that is, that every divided thing, is 
divided things, which is insignificant. 

7. Number is one and one, or one one and one, and 
so forwards; namely, one and one make the number 
two, and one one and one the number three; so are all 
other numbers made ; which is all one as if we should 
say, number is unities. 

8. To compound space of spaces, or time of times, 
is first to consider them one after another, and then 
altogether as one; as if one should reckon first the 
head, the feet, the arms, and the body, severally, and 
then for the account of them all together put man. And 
that which is so put for all the severals of which it 
consists, is called the whole ; and those severals, when 
by the division of the whole they come again to be 
considered singly, are parts thereof ; and therefore the 
whole and all the parts taken together are the same 
thing. And as I noted above, that in division it is not 
necessary to pull the parts asunder ; so in composition, 
it is to be understood, that for the making up of a 
whole there is no need of putting the parts together, 
so as to make them touch one another, but only of col- 
lecting them into one sum in the mind. For thus all 
men, being considered together, make up the whole of 
mankind, though never so much dispersed by time and 
place; and twelve hours, though the hours of several 
days, may be compounded into one number of twelve. 



OF PLACE AND TIME. 49 

9. This being well understood, it is manifest that 
nothing can rightly be called a whole, that is not con- 
ceived to be compounded of parts, and that it may be 
divided into parts ; so that if we deny that a thing has 
parts, we deny the same to be a whole. For example, 
if we say the soul can have no parts, we affirm that no 
soul can be a whole soul. Also it is manifest, that 
nothing has parts till it be divided ; and when a thing 
is divided, the parts are only so many as the division 
makes them. Again, that a part of a part is a part of 
the whole; and thus any part of the number four, as 
two, is a part of the number eight; for four is made of 
two and two; but eight is compounded of two, two, 
and four, and therefore two, which is a part of the 
part four, is also a part of the whole eight. 

10. Two spaces are said to be contiguous, when 
there is no other space betwixt them. But two times, 
betwixt which there is no other time, are called imme- 
diate, as A B, B C. And any two a -r r 

spaces, as well as times, are said 

to be continual, when they have one common part, 
as A C, B D, where the part BC ^ g q tj 

is common; and more spaces and 

times are continual, when every two which are next 
one another are continual. 

11. That part which is between two other parts, is 
called a mean; and that which is not between two 
other parts, an extreme. And of extremes, that which 
is first recokned is the bfginning, and that which last, 
the end ; and all the means together taken are the way. 
Also, extreme parts and limits are the same thing. And 
from hence it is manifest, that beginning and end de- 
pend upon the order in which we number them; and 
that to terminate or limit space and time, is the same 



50 CONCERNING BODY. 

thing with imagining their beginning and end; as also 
that every thing is finite or infinite, according as 
we imagine or not imagine it limited or terminated 
every way; and that the limits of any number are 
unities, and of these, that which is the first in our num- 
bering is the beginning, and that which we number 
last, is the end. When we say number is infinite, we 
mean only that no number is expressed; for when we 
speak of the numbers two, three, a thousand, &c. they 
are always Unite. But when no more is said but this, 
number is infinite, it is to be understood as if it were 
said, this name number is an indefinite name. 

12. Space or time is said to be finite in power, or 
terminable, when there may be assigned a number of 
finite spaces or times, as of paces or hours, than which 
there can be no greater number of the same measure 
in that space or time; and infinite in power is that 
space or time, in which a greater number of the said 
paces or hours may be assigned, than any number that 
can be given. But we must note, that, although in that 
space or time which is infinite in power, there may be 
numbered more paces or hours than any number that 
can be assigned, yet their number will always be finite ; 
for every number is finite. And therefore his ratio- 
cination was not good, that undertaking to prove the 
world to be finite, reasoned thus: // the world 
be infinite, then there may be taken in it some part 
which is distant from us an infinite number of paces: 
but no such part can be taken; wherefore the world is 
not infinite; because that consequence of the major 
proposition is false ; for in an infinite space, whatsoever 
we take or design in our mind, the distance of the same 
from us is a finite space ; for in the very designing of 
the place thereof, we put an end to that space, of which 



OF PLACE AND TIME. 51 

we ourselves are the beginning; and whatsoever any 
man with his mind cuts off both ways from infinite, he 
determines the same, that is, he makes it finite. 

Of infinite space or time, it cannot be said that it is 
a whole or one: not a whole, because not compounded 
of parts; for seeing parts, how many soever they be, 
are severally finite, they will also, when they are all 
put together, make a whole finite: nor one, because 
nothing can be said to be one, except there be another 
to compare it with; but it cannot be conceived that 
there are two spaces, or two times, infinite. Lastly, 
when we make question whether the world be finite or 
infinite, we have nothing in our mind answering to the 
name world; for whatsoever we imagine, is therefore 
finite, though our computation reach the fixed stars, or 
the ninth or tenth, nay, the thousandth sphere. The 
meaning of the question is this only, whether God has 
actually made so great an addition of body to body, as 
we are able to make of space to space. 

13. And, therefore, that which is commonly said, 
that space and time may be divided infinitely, is not to 
be so understood, as if there might be any infinite or 
eternal division; but rather to be taken in this sense, 
whatsoever is divided, is divided into such parts as may 
again be divided; or thus, the least divisible thing is not 
to be given; or, as geometricians have it, no quantity is 
so small, but a less may be taken; which may easily be 
demonstrated in this manner. Let any space or time, 
that which was thought to be the least divisible, be 
divided into two equal parts, A and B. I say either 
of them, as A, may be divided again. For suppose 
the part A to be contiguous to the part B of one side, 
and of the other side to some other space equal to B. 
This whole space, therefore, being greater than the 



52 CONCERNING BODY. 

space given, is divisible. Wherefore, if it be divided 
into two equal parts, the part in the middle, which is A, 
will be also divided into two equal parts; and there- 
fore A was divisible. 

CHAPTER VIII. 

OF BODY AND ACCIDENT. 

I. Body defined. — 2. Accident defined. — 3. How an accident 
may be understood to be in its subject. — 4. Magnitude, what 
it is. — 5. Place, what it is, and that it is immovable. — 6. 
What is full and empty. — 7. Here, there, somewhere, what 
they signify. — 8. Many bodies cannot be in one place, nor 
one body in many places. — 9. Contiguous and continual, what 
they are. — 10. The definition of motion. No motion intelli- 
gible but with time. — II. What it is to be at rest, to have 
been moved, and to be moved. No motion to be conceived, 
without the conception of past and future. — 12. A point, a 
line, superfices and solid, what they are. — 13. Equal, greater, 
and less in bodies and magnitudes, what they are. — 14. One 
and the same body has always one and the same magnitude. 
15. Velocity, what it is. — 16. Equal, greater, and less in 
times, what they are. — 17. Equal, greater, and less, in veloc- 
ity, what. — 18. Equal, greater, and less, in motion, what. — 
19. That which is at rest, will always be at rest, except it be 
moved by some external thing; and that which is moved, 
will always be moved, unless it be hindered by some exter- 
nal thing. — 20. Accidents are generated and destroyed, but 
bodies not so. — 21. An accident cannot depart from its sub- 
ject. — 22. Nor be moved. — 23. Essence, form, and matter, 
what they are. — 24. First matter, what. — 25. That the whole 
is greater than any part thereof, why demonstrated. 

I. Having understood what imaginary space is, in 
which we supposed nothing remaining without us, but 
all those things to be destroyed, that, by existing here- 
tofore, left images of themselves in our minds; let us 



OF BODY AND ACCIDENT. 53 

now suppose some one of those things to be placed 
again in the world, or created anew. It is necessary, 
therefore, that this new-created or replaced thing do 
not only fill some part of the space above mentioned, 
or be coincident and coextended with it, but also that 
it have no dependance upon our thought. And this is 
that which, for the extension of it, we commonly call 
body; and because it depends not upon our thought, 
we say is a thing subsisting of itself; as also existing, 
because without us ; and, lastly, it is called the subject, 
because it is so placed in and subjected to imaginary 
space, that it may be understood by reason, as well as 
perceived by sense. The definition, therefore, of body 
may be this, a body is that, which having no depend- 
ance upon our thought, is coincident or coextended 
with some part of space. 

2. But what an accident is cannot so easily be ex- 
plained by any definition, as by examples. Let us im- 
agine, therefore, that a body fills any space, or is 
coextended with it; that coextension is not the coex- 
tended body: and, in like manner, let us imagine that 
the same body is removed out of its place; that re- 
moving is not the removed body: or let us think the 
same not removed; that not removing or rest is not 
the resting body. What, then, are these things ? They 
are accidents of that body. But the thing in question 
is, what is an accident? which is an enquiry after that 
which we know already, and not that which we should 
enquire after. For who does not always and in the 
same manner understand him that says any thing is 
extended, or moved, or not moved? But most men 
will have it be said that an accident is something, 
namely, some part of a natural thing, when, indeed, 
it is no part of the same. To satisfy these men, as 



54 CONCERNING BODY. 

well as may be, they answer best that define an acci- 
dent to be the manner by which any body is con- 
ceived; which is all one as if they should say, an ac- 
cident is that faculty of any body, by which it works 
in us a conception of itself. Which definition, though 
it be not an answer to the question propounded, yet 
it is an answer to that question which should have been 
propounded, namely, whence does it happen that one 
part of any body appears here, another there? For 
this is well answered thus: it happens from the ex- 
tension of that body. Or, how comes it to pass that 
the whole body, by succession, is seen now here, now 
there? and the answer will be, by reason of its mo- 
tion. Or, lastly, whence is it that any body possesseth 
the same space for sometime? and the answer will 
be, because it is not moved. For if concerning the 
name of a body, that is, concerning a concrete name, 
it be asked, what is it? the answer must be made by 
definition; for the question is concerning the sig- 
nification of the name. But if it be asked concerning 
an abstract name, what is it? the cause is demanded 
why a thing appears so or so. As if it be asked, what 
is hard? The answer will be, hard is that, whereof no 
part gives place, but when the whole gives place. But 
if it be demanded, what is hardness? a cause must be 
shewn why a part does not give place, except the whole 
give place. Wherefore, I define an accident to be the 
manner of our conception of body. 

3. When an accident is said to be in a body, it is 
not so to be understood, as if any thing were con- 
tained in that body; as if, for example, redness were 
in blood, in the same manner, as blood is in a bloody 
cloth, that is, as a part in the whole; for so, an acci- 
dent would be a body also. But, as magnitude, or 



OF BODY AND ACCIDENT. 55 

rest, or motion, is in that which is great, or which 
resteth, or which is moved, (which, how it is to be 
understood, every man understands) so also it is to be 
understood, that every other accident is in its subject. 
And this, also is explicated by Aristotle no other- 
wise than negatively, namely, that an accident is in its 
subject, not as any part thereof, but so as that it may be 
away, the subject still remaining; which is right, sav- 
ing that there are certain accidents which can never 
perish except the body perish also; for no body can 
be conceived to be without extension, or without 
figure. All other accidents, which are not common 
to all bodies, but peculiar to some only, as to be at 
rest, to be moved, colour, hardness, and the like, do 
perish continually, and are succeeded by others; yet 
so, as that the body never perisheth. And as for the 
opinion that some may have, that all other accidents 
are not in their bodies in the same manner that ex- 
tension, motion, rest, or figure, are in the same; for 
example, that colour, heat, odour, virtue, vice, and the 
like, are otherwise in them, and, as they say, inherent; 
I desire they would suspend their judgment for the 
present, and expect a little, till it be found out by ratio- 
cination, whether these very accidents are not also cer- 
tain motions either of the mind of the perceiver, or of 
the bodies themselves which are perceived ; for in the 
search of this, a great part of natural philosophy con- 
sists. 

4. The extension of a body, is the same thing with 
the magnitude of it, or that which some call real space. 
But this magnitude does not depend upon our cogita- 
tion, as imaginary space doth ; for this is an effect of 
our imagination, but magnitude is the cause of it; 



56 CONCERNING BODY. 

this is an accident of the mind, that of a body existing 
out of the mind. 

5. That space, by which word I here understand 
imaginary space, which is coincident with the magni- 
tude of any body, is called the place of that body; 
and the body itself is that which we call the thing 
placed. Now place, and the magnitude of the thing 
placed, differ. First in this, that a body keeps always 
the same magnitude, both when it is at rest, and when 
it is moved; but when it is moved, it does not keep 
the same place. Secondly in this, that place is a phan- 
tasm of any body of such and such quantity and figure ; 
but magnitude is the peculiar accident of every body; 
for one body may at several times have several places, 
but has always one and the same magnitude. Thirdly 
in this, that place is nothing out of the mind, nor 
magnitude any thing within it. And lastly, place is 
feigned extension, but magnitude true extension; and 
a placed body is not extension, but a thing extended. 
Besides, place is immovable; for, seeing that which is 
moved, is understood to be carried from place to place, 
if place were moved, it would also be carried from 
place to place, so that one place must have another 
place, and that place another place, and so on infinitely, 
which is ridiculous. And as for those, that, by 
making place to be of the same nature with real space, 
would from thence maintain it to be immovable, they 
also make place, though they do not perceive they make 
it so, to be a mere phantasm. For whilst one affirms 
that place is therefore said to be immovable, because 
space in general is considered there ; if he had remem- 
bered that nothing is general or universal besides 
names or signs, he would easily have seen that that 
space, which he says is considered in general, is noth- 



OF BODY AND ACCIDENT. 57 

ing but a phantasm, in the mind or the memory, of a 
body of such magnitude and such figure. And whilst 
another says: real space is made immovable by the 
understanding; as when, under the superficies of run- 
ning water, we imagine other and other water to come 
by continual succession, that superficies fixed there 
by the understanding, is the immovable place of the 
river : what else does he make it to be but a phantasm, 
though he do it obscurely and in perplexed words? 
Lastly, the nature of place does not consist in the 
superficies of the ambient, but in solid space; for the 
whole placed body is coextended with its whole place, 
and every part of it with every answering part of the 
same place; but seeing every placed body is a solid 
thing, it cannot be understood to be coextended with 
superficies. Besides, how can any whole body be 
moved, unless all its parts be moved together with 
it? Or how can the internal parts of it be moved, 
but by leaving their place ? But the internal parts of a 
body cannot leave the superficies of an external part 
contiguous to it; and, therefore, it follows, that if 
place be the superficies of the ambient, then the parts 
of a body moved, that is, bodies moved, are not 
moved. 

6. Space, or place, that is possessed by a body, is 
called full, and that which is not so possessed, is called 
empty. 

7. Here, there, in the country, in the city, and 
other the like names, by which answer is made to the 
question where is it? are not properly names of place, 
nor do they of themselves bring into the mind the place 
that is sought; for here and there signify nothing, un- 
less the thing be shewn at the same time with the 
finger or something else; but when the eye of him 



58 CONCERNING BODY. 

that seeks, is, by pointing or some other sign, directed 
to the thing sought, the place of it is not hereby de- 
fined by him that answers, but found out by him that 
asks the question. Now such shewings as are made 
by words only, as when we say, in the country, or in 
the city, are some of greater latitude than others, as 
when we say, in the country, in the city, in such a 
street, in a house, in the chamber, in bed, &c. For 
these do, by little and little, direct the seeker nearer 
to the proper place; and yet they do not determine 
the same, but only restrain it to a lesser space, and 
signify no more, than that the place of the thing is 
within a certain space designed by those words, as a 
part is in the whole. And all such names, by which 
answer is made to the question where? have, for their 
highest genus, the name somewhere. From whence it 
may be understood, that whatsoever is somewhere, is 
in some place properly so called, which place is part of 
that greater space that is signified by some of these 
names, in the country, in the city, or the like. 

8. A body, and the magnitude, and the place there- 
of, are divided by one and the same act of the mind; 
for, to divide an extended body, and the extension 
thereof, and the idea of that extension, which is place, 
is the same with dividing any one of them; because 
they are coincident, and it cannot be done but by mind, 
that is by the division of space. From whence it is 
manifest, that neither two bodies can be together in 
the same place, nor one body be in two places at the 
same time. Not two bodies in the same place ; because 
when a body that fills its whole place is divided into 
two, the place itself is divided into two also, so that 
there will be two places. Not one body in two places ; 
for the place that a body fills being divided into two, 



OF BODY AND ACCIDENT, 59 

the placed body will be also divided into two; for, as 
I said, a place and the body that fills that place, are 
divided both together ; and so there will be two bodies. 

9. Two bodies are said to be contiguous to one 
another, and continual, in the same manner as spaces 
are ; namely, those are contiguous, between which there 
is no space. Now, by space I understand, here as 
formerly, an idea or phantasm of a body. Wherefore, 
though between two bodies there be put no other body, 
and consequently no magnitude, or, as they call it, real 
space, yet if another body may be put between them, 
that is, if there intercede any imagined space which 
may receive another body, then those bodies are not 
contiguous. And this is so easy to be understood, that 
I should wonder at some men, who being otherwise 
skilful enough in philosophy, are of a different opin- 
ion, but that I find that most of those that affect meta- 
physical subtleties wander from truth, as if they were 
led out of their way by an ignis fatuus. For can any 
man that has his natural senses, think that two bodies 
must therefore necessarily touch one another, because 
no other body is between them ? Or that there can be 
no vacuum, because vacuum is nothing, or as they call 
it, non ens? Which is as childish, as if one should 
reason thus; no man can fast, because to fast is to 
eat nothing; but nothing cannot be eaten. Continual, 
are any two bodies that have a common part; and 
more than two are continual, when every two, that 
are next to one another, are continual. 

10. Motion is a continual relinquishing of one 
place, and acquiring of another; and that place which 
is relinquished is commonly called the terminus a quo, 
as that which is acquired is called the terminus ad 
quern; I say a continual relinquishing, because no body, 



60 CONCERNING BODY. 

how little soever, can totally and at once go out of its 
former place into another, so, but that some part of 
it will be in a part of a place which is common to both, 
namely, to the relinquished and the acquired places. 
A G B I E For example, let any body be in the 
place A C B D; the same body can- 
not come into the place B D E F, 
but it must first be in G H I K, 



C H D K F whose part g H B D is common to 
both the places A C B D, and G H I K, and whose part 
B D I K, is common to both the places G H I K, and 
B D E F. Now it cannot be conceived that anything 
can be moved without time ; for time is, by the defini- 
tion of it, a phantasm, that is, a conception of motion ; 
and, therefore, to conceive that any thing may be 
moved without time, were to conceive motion without 
motion, which is impossible. 

ii. That is said to be at rest, which, during any 
time, is in one place; and that to be moved, or to have 
been moved, which, whether it be now at rest or moved, 
was formerly in another place than that which it is now 
in. From which definitions it may be inferred, first, 
that whatsoever is moved, has been moved; for if it be 
still in the same place in which it was formerly, it is at 
rest, that is, it is not moved, by the definition of rest; 
but if it be in another place, it has been moved, by the 
definition of moved. Secondly, that what is moved, 
will yet be moved; for that which is moved, leaveth the 
place where it is, and therefore will be in another 
place, and consequently will be moved still. Thirdly, 
that whatsoever is moved, is not in one place during 
any time, how little soever that time te; for by the 
definition of rest, that which is in one place during any 
time, is at rest. 



OF BODY AND ACCIDENT. 61 

There is a certain sophism against motion, which 
seems to spring from the not understanding of this 
last proposition. For they say, that, if any body be 
moved, it is moved either in the place where it is, or in 
the place where it is not; both which are false; and 
therefore nothing is moved. But the falsity lies in the 
major proposition ; for that which is moved, is neither 
moved in the place where it is, nor in the place where 
it is not; but from the place where it is, to the place 
where it is not. Indeed it cannot be denied but that 
whatsoever is moved, is moved somewhere, that is, 
within some space; but then the place of that body is 
not that whole space, but a part of it, as is said above 
in the seventh article. From what is above demon- 
strated, namely, that whatsoever is moved, has also 
been moved, and will be moved, this also may be col- 
lected, that there can be no conception of motion, with- 
out conceiving past and future time. 

12. Though there be no body which has not some 
magnitude, yet if, when any body is moved, the magni- 
tude of it be not at all considered, the way it makes is 
called a line, or one single dimension ; and the space, 
through which it passeth, is called length; and the 
body itself, a point; in which sense the earth is called 
a point, and the way of its yearly revolution, the 
ecliptic line. But if a body, which is moved, be consid- 
ered as long, and be supposed to be so moved, as that 
all the several parts of it be understood to make several 
lines, then the way of every part of that body is called 
breadth, and the space which is made is called super- 
ficies, consisting of two dimensions, one whereof to 
every several part of the other is applied whole. 
Again, if a body be considered as having superficies, 
and be understood to be so moved, that all the several 



62 CONCERNING BODY. 

parts of it describe several lines, then the way of every 
part of that body is called thickness or depth, and the 
space which is made is called solid, consisting of three 
dimensions, any two whereof are applied whole to every 
several part of the third. 

But if a body be considered as solid, then it is not 
possible that all the several parts of it should describe 
several lines; for what way soever it be moved, the 
way of the following part will fall into the way of the 
part before it, so that the same solid will still be made 
which the foremost superficies would have made by 
itself. And therefore there can be no other dimension 
in any body, as it is a body, than the three which I 
have now described; though, as it shall be shewed 
hereafter, velocity, which is motion according to length, 
may, by being applied to all the parts of a solid, make 
a magnitude of motion, consisting of four dimensions ; 
as the goodness of gold, computed in all the parts of it, 
makes the price and value thereof. 

13. Bodies, how many soever they be, that can 
fill every one the place of every one, are said to be 
equal every one to every other. Now, one body may 
fill the same place which another body filleth, though 
it be not of the same figure with that other body, if so 
be that it may be understood to be reducible to the 
same figure, either by flexion or transposition of the 
parts. And one body is greater than another body, 
when a part of that is equal to all this; and less, when 
all that is equal to a part of this. Also, magnitudes are 
equal, or greater, or lesser, than one another, for the 
same consideration, namely, when the bodies, of which 
they are the magnitudes, are either equal, or greater, 
or less, &c. 

14. One and the same body is always of one and 



OF BODY AND ACCIDENT. 63 

the same magnitude. For seeing a body and the mag- 
nitude and place thereof cannot be comprehended in 
the mind otherwise than as they are coincident, if any 
body be understood to be at rest, that is, to remain 
in the same place during some time, and the magnitude 
thereof be in one part of that time greater, and in 
another part less, that body's place, which is one and 
the same, will be coincident sometimes with greater, 
sometimes with less magnitude, that is, the same place 
will be greater and less than itself, which is impossible. 
But there would be no need at all of demonstrating a 
thing that is in itself so manifest, if there were not 
some, whose opinion concerning bodies and their mag- 
nitudes is, that a body may exist separated from its 
magnitude, and have greater or less magnitude be- 
stowed upon it, making use of this principle for the 
explication of the nature of rarnm and densum. 

15. Motion, in as much as a certain length may in 
a certain time be transmitted by it, is called velocity 
or swiftness: &c. For though swift be very often 
understood with relation to slower or less swift, as 
great is in respect of less, yet nevertheless, as magni- 
tude is by philosophers taken absolutely for extension, 
so also velocity or swiftness may be put absolutely for 
motion according to length. 

16. Many motions are said to be made in equal 
times, when every one of them begins and ends to- 
gether with some other motion, or if it had begun 
together, would also have ended together with the 
same. For time, which is a phantasm of motion, can- 
not be reckoned but by some exposed motion; as in 
dials by the motion of the sun or of the hand ; and if 
two or more motions begin and end with this motion, 
they are said to be made in equal times ; from whence 



64 CONCERNING BODY. 

also it is easy to understand what it is to be moved in 
greater or longer time, and in less time or not so long ; 
namely, that that is longer moved, which beginning 
with another, ends later; or ending together, began 
sooner. 

17. Motions are said to be equally swift, when 
equal lengths are transmitted in equal times; and 
greater swiftness is that, wherein greater length is 
passed in equal time, or equal length in less time. Also 
that swiftness by which equal lengths are passed in 
equal parts of time, is called uniform swiftness or 
motion; and of motions not uniform, such as become 
swifter or slower by equal increasings or decreasings 
in equal parts of time, are said to be accelerated or re- 
tarded uniformly. 

18. But motion is said to be greater, less, and equal, 
not only in regard of the length which is transmitted 
in a certain time, that is, in regard of swiftness only, 
but of swiftness applied to every smallest particle of 
magnitude ; for when any body is moved, every part of 
it is also moved ; and supposing the parts to be halves, 
the motions of those halves have their swiftness equal 
to one another, and severally equal to that of the whole ; 
but the motion of the whole is equal to those two 
motions, either of which is of equal swiftness with it ; 
and therefore it is one thing for two motions to be 
equal to one another, and another thing for them to 
be equally swift. And this is manifest in two horses 
that draw abreast, where the motion of both the horses 
together is of equal swiftness with the motion of either 
of them singly ; but the motion of both is greater than 
the motion of one of them, namely, double. Wherefore 
motions are said to be simply equal to one another, 
when the swiftness of one, computed in every part of 



OF BODY AND ACCIDENT. 65 

its magnitude, is equal to the swiftness of the other 
computed also in every part of its magnitude: and 
greater than one another, when the swiftness of one 
computed as above, is greater than the swiftness of the 
other so computed; and less, when less. Besides, the 
magnitude of motion computed in this manner is that 
which is commonly called force. 

19. Whatsoever is at rest, will always be at rest, 
unless there be some other body besides it, which, by 
endeavoring to get into its place by motion, suffers it 
no longer to remain at rest. For suppose that some 
finite body exist and be at rest, and that all space 
besides be empty ; if now this body begin to be moved, 
it will certainly be moved some way ; seeing therefore 
there was nothing in that body which did not dispose 
it to rest, the reason why it is moved this way is in 
something out of it ; and in like manner, if it had been 
moved any other way, the reason of motion that way 
had also been in something out of it ; but seeing it was 
supposed that nothing is out of it, the reason of its 
motion one way would be the same with the reason of 
its motion every other way, wherefore it would be 
moved alike all ways at once ; which is impossible. 

In like manner, whatsoever is moved, will always be 
moved, except there be some other body besides it, 
which causeth it to rest. For if we suppose nothing to 
be without it, there will be no reason why it should 
rest now, rather than at another time; wherefore its 
motion would cease in every particle of time alike; 
which is not intelligible. 

20. When we say a living creature, a tree, or any 
other specified body is generated or destroyed, it is not 
to be so understood as if there were made a body of 
that which is not-body, or not a body of a body, but of a 



66 CONCERNING BODY. 

living creature not a living creature, of a tree not a 
tree, &c. that is, that those accidents for which we call 
one thing a living creature, another thing a tree, and 
another by some other name, are generated and de- 
stroyed ; and that therefore the same names are not to 
be given to them now, which were given them before. 
But that magnitude for which we give to any thing 
the name of body is neither generated nor destroyed. 
For though we may feign in our mind that a point 
may swell to a huge bulk, and that this may again con- 
tract itself to a point ; that is, though we may imagine 
something to rise where before was nothing, and noth- 
ing to be there where before was something, yet we 
cannot comprehend in our mind how this may possibly 
be done in nature. And therefore philosophers, who 
tie themselves to natural reason, suppose that a body 
can neither be generated nor destroyed, but only that 
it may appear otherwise than it did to us, that is, under 
different species, and consequently be called by other 
and other names; so that that which is now called man, 
may at another time have the name of not-man; but 
that which is once called body, can never be called not- 
body. But it is manifest, that all other accidents be- 
sides magnitude or extension may be generated and de- 
stroyed; as when a white thing is made black, the 
whiteness that was in it perisheth, and the blackness 
that was not in it is now generated ; and therefore bod- 
ies, and the accidents under which they appear 
diversely, have this difference, that bodies are things, 
and not generated; accidents are generated, and not 
things. 

21. And therefore, when any thing appears other- 
wise than it did by reason of other and other acci- 
dents, it is not to be thought that an accident goes out 






OF BODY AND ACCIDENT. 67 

of one subject into another, (for they are not, as I 
said above, in their subjects as a part in the whole, or 
as a contained thing in that which contains it, or as a 
master of a family in his house,) but that one accident 
perisheth, and another is generated. For example, 
when the hand, being moved, moves the pen, motion 
does not go out of the hand into the pen; for so the 
writing might be continued though the hand stood 
still ; but a new motion is generated in the pen, and is 
the pen's motion. 

22. And therefore also it is improper to say, an 
accident is moved; as when, instead of saying, figure 
is an accident of a body carried away, we say, a body 
carries away its figure. 

23. Now that accident for which we give a certain 
name to any body, or the accident which denominates its 
subject, is commonly called the essence thereof; as 
rationality is the essence of a man; whiteness, of any 
white thing, and extension the essence of a body. And 
the same essence, in as much as it is generated, is called 
the form. Again, a body, in respect of any accident, 
is called the subject, and in respect of the form it is 
called the matter. 

Also, the production or perishing of any accident 
makes its subject be said to be changed; only the pro- 
duction or perishing of form makes it be said it is 
generated or destroyed; but in all generation and muta- 
tion, the name of matter still remains. For a table 
made of wood is not only wooden, but wood; and a 
statue of brass is brass as well as brazen; though 
Aristotle, in his Metaphysics, says that whatsoever is 
made of any thing ought not to be called iicavb; but 
ckuvlvov; as that which is made of wood, not ivXov 
but £vAivov , that is, not wood, but wooden. 



68 CONCERNING BODY. 

24. And as for that matter which is common to all 
things, and which philosophers, following Aristotle, 
usually call materia prima, that is, first matter, it is not 
any body distinct from all other bodies, nor is it one of 
them. What then is it? A mere name; yet a name 
which is not of vain use; for it signifies a conception 
of body without the consideration of any form or other 
accident except only magnitude or extension, and apt- 
ness to receive form and other accident. So that when- 
soever we have use of the name body in general, if we 
use that of materia prima, we do well. For as when a 
man not knowing which was first, water or ice, would 
find out which of the two were the matter of both, he 
would be fain to suppose some third matter which were 
neither of these two ; so he that would find out what is 
the matter of all things, ought to suppose such as is 
not the matter of anything that exists. Wherefore 
materia prima is nothing; and therefore they do not 
attribute to it either form or any other accident besides 
quantity; whereas all singular things have their forms 
and accidents certain. 

Materia prima, therefore, is body in general, that is, 
body considered universally, not as having neither 
form nor any accident, but in which no form nor any 
other accident but quantity are at all considered, that 
is, they are not drawn into argumentation. 

25. From what has been said, those axioms may be 
demonstrated, which are assumed by Euclid in the be- 
ginning of his first element, about the equality and in- 
equality of magnitudes ; of which, omitting the rest, I 
will here demonstrate only this one, the whole is 
greater than any part thereof; to the end that the 
reader may know that those axioms are not indemon- 
strable, and therefore not principles of demonstration; 



OF CAUSE AND EFFECT. 69 

and from hence learn to be wary how he admits any 
thing for a principle, which is not at least as evident as 
these are. Greater is defined to be that, whose part is 
equal to the whole of another. Now if we suppose any 
whole to be A, and a part of it to be B; seeing the 
whole B is equal to itself, and the same B is a part of 
A ; therefore a part of A will be equal to the whole B. 
Wherefore, by the definition above, A is greater than 
B ; which was to be proved. 

CHAPTER IX. 

OF CAUSE AND EFFECT. 

I. Action and passion, what they are. — 2. Action and passion 
mediate and immediate. — 3. Cause simply taken. Cause 
without which no effect follows, or cause necessary by sup- 
position. — 4. Cause efficient and material. — 5. An entire 
cause is always sufficient to produce its effect. At the same 
instant that the cause is entire, the effect is produced. 
Every effect has a necessary cause. — 6. The generation of 
effects is continual. What is the beginning in causation. — 7. 
No cause of motion but in a body contiguous and moved. — 
8. The same agents and patients, if alike disposed, produce 
like effects though at different times. — 9. All mutation is 
motion. — 10. Contingent accidents, what they are. 

I. A body is said to work upon or act, that is to say, 
do something to another body, when it either generates 
or destroys some accident in it : and the body in which 
an accident is generated or destroyed is said to suffer, 
that is, to have something done to it by another body ; 
as when one body by putting forwards another body 
generates motion in it, it is called the agent ; and the 
body in which motion is so generated, is called the 
patient ; so fire that warms the hand is the agent, and 



70 CONCERNING BODY. 

the hand, which is warmed, is the patient That acci- 
dent, which is generated in the patient, is called the 

EFFECT. 

2. When an agent and patient are contiguous to 
one another, their action and passion are then said to 
be immediate ', otherwise, mediate; and when another 
body, lying betwixt the agent and patient, is contigu- 
ous to them both, it is then itself both an agent and a 
patient ; an agent in respect of the body next after it, 
upon which it works, and a patient in respect of the 
body next before it, from which it suffers. Also, if 
many bodies be so ordered that every two which are 
next to one another be contiguous, then all those that 
are betwixt the first and the last are both agents and 
patients, and the first is an agent only, and the last a 
patient only. 

3. An agent is understood to produce its deter- 
mined or certain effect in the patient, according to 
some certain accident or accidents, with which both it 
and the patient are affected; that is to say, the agent 
hath its effect precisely such, not because it is a body, 
but because such a body, or so moved. For otherwise 
all agents, seeing they are all bodies alike, would pro- 
duce like effects in all patients. And therefore the 
fire, for example, does not warm, because it is a body, 
but because it is hot; nor does one body put forward 
another body because it is a body, but because it is 
moved into the place of that other body. The cause, 
therefore, of all effects consists in certain accidents 
both in the agents and in the patients; which when 
they are all present, the effect is produced ; but if any 
one of them be wanting, it is not produced; and that 
accident either of the agent or patient, without which 
the effect cannot be produced, is called causa sine qua 



OF CAUSE AND EFFECT. 71 

non, or cause necessary by supposition, as also the 
cause requisite for the production of the effect. But a 
cause simply, or an entire cause, is the aggregate of 
all the accidents both of the agents how many soever 
they be, and of the patient, put together; which when 
they are all supposed to be present, it cannot be under- 
stood but that the effect is produced at the same in- 
stant; and if any one of them be wanting, it cannot be 
understood but that the effect is not produced. 

4. The aggregate of accidents in the agent or 
agents, requisite for the production of the effect, the 
effect being produced, is called the efficient cause 
thereof; and the aggregate of accidents in the patient, 
the effect being produced, is usually called the 
material cause; I say the effect being produced; for 
where there is no effect there can be no cause; for 
nothing can be called a cause, where there is nothing 
that can be called an effect. But the efficient and 
material causes are both but partial causes, or parts of 
that cause, which in the next precedent article I called 
an entire cause. And from hence it is manifest, that 
the effect we expect, though the agents be not defective 
on their part, may nevertheless be frustrated by a 
defect in the patient ; and when the patient is sufficient, 
by a defect in the agents. 

5. An entire cause is always sufficient for the pro- 
duction of its effect, if the effect be at all possible. For 
let any effect whatsoever be propounded to be pro- 
duced ; if the same be produced, it is manifest that the 
cause which produced it was a sufficient cause ; but if 
it be not produced, and yet be possible, it is evident 
that something was wanting either in some agent, or 
in the patient, without which it could not be produced ; 
that is, that some accident was wanting which was 



72 CONCERNING BODY. 

requisite for its production; and therefore, that cause 
was not entire, which is contrary to what was sup- 
posed. 

It follows also from hence, that in whatsoever in- 
stant the cause is entire, in the same instant the effect 
is produced. For if it be not produced, something is 
still wanting, which is requisite for the production of 
it; and therefore the cause was not entire, as was 
supposed. 

And seeing a necessary cause is defined to be that, 
which being supposed, the effect cannot but follow; 
this also may be collected, that whatsoever effect is 
produced at any time, the same is produced by a neces- 
sary cause. For whatsoever is produced, in as much 
as it is produced, had an entire cause, that is, had all 
those things, which being supposed, it cannot be under- 
stood but that the effect follows; that is, it had a 
necessary cause. And in the same manner it may be 
shewn, that whatsoever effects are hereafter to be pro- 
duced, shall have a necessary cause; so that all the 
effects that have been, or shall be produced, have their 
necessity in things antecedent. 

6. And from this, that whensoever the cause is 
entire, the effect is produced in the same instant, it is 
manifest that causation and the production of effects 
consist in a certain continual progress ; so that as there 
is a continual mutation in the agent or agents, by the 
working of other agents upon them, so also the patient, 
upon which they work, is continually altered and 
changed. For example: as the heat of the fire in- 
creases more and more, so also the effects thereof, 
namely, the heat of such bodies as are next to it, and 
again, of such other bodies as are next to them, increase 
more and more accordingly; which is already no little 






OF CAUSE AND EFFECT. 73 

argument that all mutation consists in motion only; 
the truth whereof shall be further demonstrated in the 
ninth article. But in this progress of causation, that 
is, of action and passion, if any man comprehend in 
his imagination a part thereof, and divide the same into 
parts, the first part or beginning of it cannot be con- 
sidered otherwise than as action or cause; for, if it 
should be considered as effect or passion, then it would 
be necessary to consider something before it, for its 
cause or action; which cannot be, for nothing can be 
before the beginning. And in like manner, the last 
part is considered only as effect; for it cannot be 
called cause, if nothing follow it; but after the last, 
nothing follows. And from hence it is, that in all 
action the beginning and cause are taken for the same 
thing. But every one of the intermediate parts are 
both action and passion, and cause and effect, accord- 
ing as they are compared with the antecedent or subse- 
quent part. 

7. There can be no cause of motion, except in a 
body contiguous and moved. For let there be any two 
bodies which are not contiguous, and betwixt which 
the intermediate space is empty, or, if filled, filled with 
another body which is at rest ; and let one of the pro- 
pounded bodies be supposed to be at rest ; I say it shall 
always be at rest. For it if shall be moved, the cause 
of that motion, by the 8th chapter, article 19, will be 
some external body; and, therefore, if between it and 
that external body there be nothing but empty space, 
then whatsoever the disposition be of that external 
body or of the patient itself, yet if it be supposed to be 
now at rest, we may conceive it will continue so till it 
be touched by some other body. But seeing cause, by 



74 CONCERNING BODY. 

the definition, is the aggregate of all such accidents, 
which being supposed to be present, it cannot be con- 
ceived but that the effect will follow, those accidents, 
which are either in external bodies, or in the patient it- 
self, cannot be the cause of future motion. And in like 
manner, seeing we may conceive that whatsoever is at 
rest will still be at rest, though it be touched by some 
other body, except that other body be moved; there- 
fore in a contiguous body, which is at rest, there can 
be no cause of motion. Wherefore there is no cause 
of motion in any body, except it be contiguous and 
moved. 

The same reason may serve to prove that whatsoever 
is moved, will always be moved on in the same way 
and with the same velocity, except it be hindered by 
some other contiguous and moved body; and conse- 
quently that no bodies, either when they are at rest, or 
when there is an interposition of vacuum, can generate 
or extinguish or lessen motion in other bodies. There 
is one that has written that things moved are more re- 
sisted by things at rest, than by things contrarily 
moved; for this reason, that he conceived motion not 
to be so contrary to motion as rest. That which de- 
ceived him was, that the words rest and motion are but 
contradictory names; whereas motion, indeed, is not 
resisted by rest, but by contrary motion. 

8. But if a body work upon another body at one 
time, and afterwards the same body work upon the 
same body at another time, so that both the agent and 
patient, and all their parts, be in all things as they were ; 
and there be no difference, except only in time, that is, 
that one action be former, the other later in time ; it is 
manifest of itself, that the effects will be equal and 
like, as not differing in anything besides time. And 



OF CAUSE AND EFFECT. 75 

as effects themselves proceed from their causes, so the 
diversity of them depends upon the diversity of their 
causes also. 

9. This being true, it is necessary that mutation 
can be nothing else but motion of the parts of that 
body which is changed. For first, we do not say any- 
thing is changed, but that which appears to our senses 
otherwise than it appeared formerly. Secondly, both 
those appearances are effects produced in the sentient ; 
and, therefore, if they be different, it is necessary, by 
the preceding article, that either some part of the 
agent, which was formerly at rest, is now moved, and 
so the mutation consists in this motion; or some part, 
which was formerly moved, is now otherwise moved, 
and so also the mutation consists in this new motion ; 
or which, being formerly moved, is now at rest, which, 
as I have shewn above, cannot come to pass without 
motion; and so again, mutation is motion; or lastly, 
it happens in some of these manners to the patient, or 
some of its parts; so that mutation, howsoever it be 
made, will consist in the motion of the parts, either of 
the body which is perceived, or of the sentient body, 
or of both. jMutation therefore is motion, namely, of 
the parts either of the agent or of the patient; which 
was to be demonstrated. And to this it is consequent, 
that rest cannot be the cause of anything, nor can any 
action proceed from it; seeing neither motion nor 
mutation can be caused by it.^ 

10. Accidents, in respect of other accidents which 
precede them, or are before them in time, and upon 
which they do not depend as upon their causes, are 
called contingent accidents ; I say, in respect of those 
accidents by which they are not generated; for, in 
respect of their causes, all things come to pass with 



76 CONCERNING BODY. 

equal necessity; for otherwise they would have no 
causes at all; which, of things generated, is not in- 
telligible. 

CHAPTER X. 

OF POWER AND ACT. 

I. Power and cause are the same thing. — 2. An act is pro- 
duced at the same instant in which the power is plenary. — 
3. Active and passive power are parts only of plenary power. 
— 4. An act, when said to be possible. — 5. An act necessary 
and contingent, what. — 6. Active power consists in motion. — 
7. Cause, formal and final, what they are. 

i. Correspondent to cause and effect, are power 
and act; nay, those and these are the same things; 
though, for divers considerations, they have divers 
names. For whensoever any agent has all those acci- 
dents which are necessarily requisite for the produc- 
tion of some effect in the patient, then we say that agent 
has power to produce that effect, if it be applied to a pa- 
tient. But, as I have shewn in the precedent chapter, 
those accidents constitute the efficient cause ; and there- 
fore the same accidents, which constitute the efficient 
cause, constitute also the power of the agent. Where- 
fore the power of the agent and the efficient cause are 
the same thing. But they are considered with this dif- 
ference, that cause is so called in respect to the effect 
already produced, and power in respect of the same ef- 
fect to be produced hereafter; so that cause respects 
the past, power the future time. Also, the power of 
the agent is that which is commonly called active 
power. 

In like manner, whensoever any patient has all those 



OF POWER AND ACT. 77 

accidents which it is requisite it should have, for the 
production of some effect in it, we say it is in the 
power of that patient to produce that effect, if it be 
applied to a fitting agent. But those accidents, as is 
defined in the precedent chapter, constitute the material 
cause; and therefore the power of the patient, com- 
monly called passive power, and material cause, are the 
same thing; but with this different consideration, that 
in cause the past time, and in power the future, is 
respected. Wherefore the power of the agent and 
patient together, which may be called entire or plenary 
power, is the same thing with entire cause; for they 
both consist in the sum or aggregate of all the acci- 
dents, as well in the agent as in the patient, which are 
requisite for the production of the effect. Lastly, as 
the accident produced is, in respect of the cause, called 
an effect, so in respect of the power, it is called an act. 

2. As therefore the effect is produced in the same 
instant in which the cause is entire, so also every act 
that may be produced, is produced in the same instant 
in which the power is plenary. And as there can be 
no effect but from a sufficient and necessary cause, so 
also no act can be produced but by sufficient power, or 
that power by which it could not but be produced. 

3. And as it is manifest, as I have shewn, that the 
efficient and material causes are severally and by them- 
selves parts only of an entire cause, and cannot produce 
any effect but by being joined together, so also power, 
active and passive, are parts only of plenary and entire 
power ; nor, except they be joined, can any act proceed 
from them; and therefore these powers, as I said in 
the first article, are but conditional, namely, the agent 
has power, if it be applied to a patient; and the patient 
has power, if it be applied to an agent; otherwise 



78 CONCERNING BODY. 

neither of them have power, nor can the accidents, 
which are in them severally, be properly called powers ; 
nor any action be said to be possible for the power of 
the agent alone or of the patient alone. 

4. For that is an impossible act, for the production 
of which there is no power plenary. For seeing ple- 
nary power is that in which all things concur, which 
are requisite for the production of an act, if the power 
shall never be plenary, there will always be wanting 
some of those things, without which the act cannot be 
produced ; wherefore that act shall never be produced ; 
that is, that act is impossible : and every act, which is 
not impossible, is possible. Every act, therefore, 
which is possible, shall at some time be produced ; for 
if it shall never be produced, then those things shall 
never concur which are requisite for the production of 
it; wherefore that act is impossible, by the definition; 
which is contrary to what was supposed. 

5. A necessary act is that, the production whereof 
it is impossible to hinder ; and therefore every act, that 
shall be produced, shall necessarily be produced; for, 
that it shall not be produced, is impossible ; because, as 
is already demonstrated, every possible act shall at 
some time be produced; nay, this proposition, what 
shall be, shall be, is as necessary a proposition as this, 
a man is a man. 

But here, perhaps, some man may ask whether those 
future things, which are commonly called contingents, 
are necessary. I say, therefore, that generally all con- 
contingents have their necessary causes, as is shewn in 
the preceding chapter; but are called contingents in 
respect of other events, upon which they do not de- 
pend; as the rain, which shall be tomorrow, shall be 
necessary, that is, from necessary causes ; but we think 






OF POWER AND ACT. 79 

and say it happens by chance, because we do not yet 
perceive the causes thereof, though they exist now; 
for men commonly call that casual or contingent, 
whereof they do not perceive the necessary cause; 
and in the same manner they used to speak of things 
past, when not knowing whether a thing be done or 
no, they say it is possible it never was done. 

Wherefore, all propositions concerning future 
things, contingent or not contingent, as this, it will rain 
tomorrow, or this, tomorrow the sun will rise, are 
either necessarily true, or necessarily false ; but we call 
them contingent because we do not yet know whether 
they be true or false ; whereas their verity depends not 
upon our knowledge, but upon the foregoing of their 
causes. But there are some, who though they confess 
this whole proposition, tomorrow it will either rain, or 
not rain, to be true, yet they will not acknowledge the 
parts of it, as, tomorrow it will rain, or, tomorrow it 
will not rain, to be either of them true by itself; be- 
cause they say neither this nor that is true determi- 
nately. But what is this determinately true, but true 
upon our knowledge, or evidently true? And there- 
fore they say no more but that it is not yet known 
whether it be true or no; but they say it more ob- 
scurely, and darken the evidence of the truth with the 
same words, with which they endeavour to hide their 
own ignorance. 

6. In the 9th article of the preceding chapter, I 
have shewn that the efficient cause of all motion and 
mutation consists in the motion of the agent, or agents ; 
and in the first article of this chapter, that the power of 
the agent is the same thing with the efficient cause. 
From whence it may be understood, that all active 
power consists in motion also ; and that power is not a 



80 CONCERNING BODY. 

certain accident, which differs from all acts, but is, 
indeed, an act, namely, motion, which is therefore 
called power, because another act shall be produced by 
it afterwards. For example, if of three bodies the first 
put forward the second, and this the third, the motion 
of the second, in respect of the first which produceth 
it, is the act of the second body ; but, in respect of the 
third, it is the active power of the same second body. 

7. The writers of metaphysics reckon up two 
other causes besides the efficient and material, namely, 
the essence, which some call the formal cause, and the 
end, or final cause; both which are nevertheless 
efficient causes. For when it is said the essence of a 
thing is the cause thereof, as to be rational is the cause 
of man, it is not intelligible; for it is all one, as if it 
were said, to be a man is the cause of man; which is 
not well said. And yet the knowledge of the essence 
of anything, is the cause of the knowledge of the thing 
itself; for, if I first know that a thing is rational, I 
know from thence, that the same is man; but this is no 
other than an efficient cause. A final cause has no 
place but in such things as have sense and will; and 
this also I shall prove hereafter to be an efficient cause. 

CHAPTER XL 

OF IDENTITY AND DIFFERENCE. 

I. What it is for one thing to differ from another.— 2. To 
differ in number, magnitude, species, and genus, what.— 3. 
What is relation, proportion, and relatives. — 4. Proportion- 
als, what. — 5. The proportion of magnitudes to one another, 
wherein it consists. — 6. Relation is no new accident, but one 
of those that were in the relative before the relation or 
comparison was made. Also the causes of accidents in the 






OF IDENTITY AND DIFFERENCE. 81 

correlatives, are the cause of relation. — 7. Of the beginning 
of individuation. 

i. Hitherto I have spoken of body simply, and 
accidents common to all bodies, as magnitude, motion, 
rest, action, passion, power, possible, &c. ; and I should 
now descend to those accidents by which one body is 
distinguished from another but that it is first to be de- 
clared what it is to be distinct and not distinct, namely, 
what are the same and different ; for this also is com- 
mon to all bodies, that they may be distinguished and 
differenced from one another. Now, two bodies are 
said to differ from one another, when something may 
be said of one of them, which cannot be said of the 
other at the same time. 

2. And, first of all, it is manifest that no two bodies 
are the same; for seeing they are two, they are in two 
places at the same time; as that, which is the same, is 
at the same time in one and the same place. All bodies 
therefore differ from one another in number, namely, 
as one another ; so that the same and different in num- 
ber, are names opposed to one another by contradic- 
tion. 

In magnitude bodies differ when one is greater than 
another, as a cubit long, and two cubits long, of two 
pound weight, and of three pound weight. And to 
these, equals are opposed. 

Bodies which differ more than in magnitude, are 
called unlike; and those, which differ only in magni- 
tude, like. Also, of unlike bodies, some are said to 
differ in the species, other in the genus; in the species, 
when their difference is perceived by one and the same 
sense, as white and black; and in the genus, when their 



82 CONCERNING BODY. 

difference is not perceived but by divers senses, as 
white and hot. 

3. And the likeness, or unlikeness, equality, or in- 
equality of one body to another, is called their rela- 
tion; and the bodies themselves relatives or correla- 
tives; Aristotle calls them rd 7rpos ti ; the first whereof 
is usually named the antecedent, and the second the 
consequent; and the relation of the antecedent to the 
consequent, according to magnitude, namely, the equal- 
ity, the excess or defect thereof, is called the propor- 
tion of the antecedent to the consequent ; so that pro- 
portion is nothing but the equality or inequality of the 
magnitude of the antecedent compared to the magni- 
tude of the consequent by their difference only, or com- 
pared also with their difference. For example, 
the proportion of three to two consists only in 
this, that three exceeds two by unity; and the 
proportion of two to five in this, that two, compared 
with five, is deficient of it by three, either simply, or 
compared with the numbers different ; and therefore in 
the proportion of unequals, the proportion of the less to 
the greater, is called defect ; and that of the greater to 
the less, excess. 

4. Besides, of unequals, some are more, some less, 
and some equally unequal; so that there is proportion 
of proportions, as well as of magnitudes ; namely, 
where two unequals have relation to two other un- 
equals ; as, when the inequality which is between 2 and 
3, is compared with the inequality which is between 
4 and 5. In which comparison there are always four 
magnitudes ; or, which is all one, if there be but three, 
the middle most is twice numbered ; and if the propor- 
tion of the first to the second, be equal to the propor- 
tion of the third to the fourth, then the four are said 



OF IDENTITY AND DIFFERENCE. _ 83 

to be proportionals; otherwise they are not propor- 
tionals. 

5. The proportion of the antecendent to the conse- 
quent consists in their difference, not only simply taken, 
but also as compared with one of the relatives ; that is, 
either in that part of the greater, by which it exceeds 
the less, or in the remainder, after the less is taken out 
of the greater ; as the proportion of two to five consists 
in the three by which five exceeds two, not in three 
simply only, but also as compared with five or two. 
For though there be the same difference between two 
and five, which is between nine and twelve, namely 
three, yet there is not the same inequality ; and there- 
fore the proportion of two to five is not in all relation 
the same with that of nine to twelve, but only in that 
which is called arithmetical. 

6. But we must not so think of relation, as if it 
were an accident differing from all the other accidents 
of the relative ; but one of them, namely, that by which 
the comparison is made. For example, the likeness of 
one white to another white, or its unlikeness to black, 
is the same accident with its whiteness; and equality 
and inequality, the same accident with the magnitude 
of the thing compared, though under another name: 
for that which is called white or great, when it is not 
compared with something else, the same when it is 
compared, is called like or unlike, equal or unequal. 
And from this it follows that the causes of the acci- 
dents, which are in relatives, are the causes also of 
likeness, unlikeness, equality and inequality; namely, 
that he, that makes two unequal bodies, makes also 
their inequality; and he, that makes a rule and an 
action, makes also, if the action be congruous to the 
rule, their congruity; if incongruous, their incongru- 



84 CONCERNING BODY. 

ity. And thus much concerning comparison of one 
body with another. 

7. But the same body may at different times be 
compared with itself. And from hence springs a great 
controversy among philosophers about the beginning 
of individuation, namely, in what sense it may be con- 
ceived that a body is at one time the same, at another 
time not the same it was formerly. For example, 
whether a man grown old be the same man he was 
whilst he was young, or another man; or whether a 
city be in different ages the same, or another city. 
Some place individuity in the unity of matter; others 
in the unity of form; and one says it consists in the 
unity of the aggregate of all the accidents together. 
For matter, it is pleaded that a lump of wax, whether 
it be spherical or cubical, is the same wax, because the 
same matter. For form, that when a man is grown 
from an infant to be an old man, though his matter 
be changed, yet he is still the same numerical man; 
for that identity, which cannot be attributed to the mat- 
ter, ought probably to be ascribed to the form. For 
the aggregate of accidents, no instance can be made; 
but because, when any new accident is generated, a 
new name is commonly imposed on the thing, therefore 
he, that assigned this cause of individuity, thought the 
thing itself also was become another thing. Accord- 
ing to the first opinion, he that sins, and he that is 
punished, should not be the same man, by reason of 
the perpetual flux and change of man's body; nor 
should the city, which makes laws in one age and 
abrogates them in another, be the same city; which 
were to confound all civil rights. According to the 
second opinion, two bodies existing both at once, 
would be one and the same numerical body. For if, 



OF IDENTITY AND DIFFERENCE. 85 

for example, that ship of Theseus, concerning the 
difference whereof made by continual reparation in 
taking out the old planks and putting in new, the soph- 
isters of Athens were wont to dispute, were, after all 
the planks were changed, the same numerical ship it 
was at the beginning; and if some man had kept the 
old planks as they were taken out, and by putting them 
afterwards together in the same order, had again made 
a ship of them, this, without doubt, had also been 
the same numerical ship with that which was at 
the beginning; and so there would have been two 
ships numerically the same, which is absurd. But, 
according to the third opinion, nothing would be the 
same it was ; so that a man standing would not be the 
same he was sitting; nor the water, which is in 
the vessel, the same with that which is poured out of it. 
Wherefore the beginning of individuation is not always 
to be taken either from matter alone, or from form 
alone. 

But we must consider by what name anything is 
called, when we inquire concerning the identity of it. 
For it is one thing to ask concerning Socrates, whether 
he be the same man, and another to ask whether he 
be the same body; for his body, when he is old, can- 
not be the same it was when he was an infant, by 
reason of the difference of magnitude; for one body 
has always one and the same magnitude; yet, never- 
theless, he may be the same man. And therefore, 
whensoever the name, by which it is asked whether 
a thing be the same it was, is given it for the matter 
only, then, if the matter be the same, the thing also 
is individually the same; as the water, which was in 
the sea, is the same which is afterwards in the cloud ; 
and any body is the same, whether the parts of it be 



86 CONCERNING BODY. 

put together, or dispersed ; or whether it be congealed, 
or dissolved. Also, if the name be given for such 
form as is the beginning of motion, then, as long as 
that motion remains, it will be the same individual 
thing; as that man will be always the same, whose ac- 
tions and thoughts proceed all from the same begin- 
ning of motion, namely, that which was in his genera- 
tion ; and that will be the same river which flows from 
one and the same fountain, whether the same water, 
or other water, or something else than water, flow from 
thence; and that the same city, whose acts proceed 
continually from the same institution, whether the 
men be the same or no. Lastly, if the name be given 
for some accident, then the identity of the thing will 
depend upon the matter ; for, by the taking away and 
supplying of matter, the accidents that were, are de- 
stroyed, and other new ones are generated, which 
cannot be the same numerically ; so that a ship, which 
signifies matter so figured, will be the same as long 
as the matter remains the same; but if no part of 
the matter be the same, then it is numerically another 
ship; and if part of the matter remain and part be 
changed, then the ship will be partly the same, and 
partly not the same. 

CHAPTER XII*. 

OF QUANTITY. 

I. The definition of quantity. — 2. The exposition of quantity, 
what it is. — 3. How line, superficies, and solid are exposed. 
4. How time is exposed. — 5. How number is exposed. — 6. 



*For list of the writings of Hobbes on mathematics, cf. 
P- xviii. 



OF QUANTITY. 87 

How velocity is exposed. — 7. How weight is exposed. — 8 
How the proportion of magnitudes is exposed. — 9. How the 
proportion of times and velocities is exposed. 

1. What and how manifold dimension is, has been 
said in the 8th chapter, namely, that there are three 
dimensions, line or length, superficies, and solid ; every 
one of which, if it be determined, that is, if the limits 
of it be made known, is commonly called quantity; 
for by quantity all men understand that which is sig- 
nified by that word, by which answer is made to the 
question, How much is it? Whensoever, therefore, it 
is asked, for example, How long is the journey? it is 
not answered indefinitely, length; nor, when it is asked, 
How big is the Held? is it answered indefinitely, super- 
Hcies; nor, if a man ask, How great is the bulk? indefi- 
nitely, solid: but it is answered determinately, the jour- 
ney is a hundred miles ; the field is a hundred acres ; 
the bulk is a hundred cubical feet; or at least in 
some such manner, that the magnitude of the thing 
enquired after may by certain limits be comprehended 
in the mind. Quantity, therefore, cannot otherwise 
be defined, than to be a dimension determined, or a 
dimension, whose limits are set out, either by their 
place, or by some comparison. 

2. And quantity is determined two ways; one, by 
the sense, when some sensible object is set before it; 
as when a line, a superficies or solid, of a foot or cubit, 
marked out in some matter, is objected to the eyes; 
which way of determining, is called exposition, and 
the quantity so known is called exposed quantity; the 
other by memory, that is, by comparison with some 
exposed quantity. In the first manner, when it is 
asked of what quantity a thing is, it is answered, 



88 CONCERNING BODY. 

of such quantity as you see exposed. In the second 
manner, answer cannot be made but by comparison 
with some exposed quantity; for if it be asked, how 
long is the way? the answer is, so many thousand 
paces; that is, by comparing the way with a pace, 
or some other measure, determined and known by 
exposition ; or the quantity of it is to some other quan- 
tity known by exposition, as the diameter of a square 
is to the side of the same, or by some other the like 
means. But it is to be understood, that the quantity 
exposed must be some standing or permanent thing, 
such as is marked out in consistent or durable mat- 
ter ; or at least something which is revocable to sense ; 
for otherwise no comparison can be made by it. See- 
ing, therefore, by what has been said in the next pre- 
ceding chapter, comparison of one magnitude with 
another is the same thing with proportion ; it is mani- 
fest, that quantity determined in the second manner 
is nothing else but the proportion of a dimension not 
exposed to another which is exposed; that is, the 
comparison of the equality or inequality thereof with 
an exposed quantity. 

•3. Lines, superficies, and solids, are exposed, first, 
by motion, in such manner as in the 8th chapter I have 
said they are generated; but so as that the marks 
of such motion be permanent; as when they are de- 
signed upon some matter, as a line upon paper; or 
graven in some durable matter. Secondly, by appo- 
sition; as when one line or length is applied to another 
line or length, one breadth to another breadth, and 
one thickness to another thickness; which is as much 
as to describe a line by points, a superficies by lines, 
and a solid by superficies ; saving that by points in this 
place are to be understood very short lines; and, by 



OF QUANTITY. 89 

superficies, very thin solids. Thirdly, lines and super- 
ficies may be exposed by section, namely, a line may be 
made by cutting an exposed superficies; and a super- 
ficies, by the cutting of an exposed solid. 

4. Time is exposed, not only by the exposition of 
a line, but also of some moveable thing, which is 
moved uniformly upon that line, or at least is sup- 
posed so to be moved. For, seeing time is an idea 
of motion, in which we consider former and latter, that 
is succession, it is not sufficient for the exposition of 
time that a line be described; but we must also have 
in our mind an imagination of some moveable thing 
passing over that line; and the motion of it must be 
uniform, that time may be divided and compounded 
as often as there shall be need. And, therefore, when 
philosophers, in their demonstrations, draw a line, 
and say, Let that line be time, it is to be understood as 
if they said, Let the conception of uniform motion upon 
that line, be time. For though the circles in dials be 
lines, yet they are not of themselves sufficient to note 
time by, except also there be, or be supposed to be, 
a motion of the shadow or the hand. 

5. Number is exposed, either by the exposition of 
points, or of the names of number, one, two, three, 
&c; and those points must not be contiguous, so as 
that they cannot be distinguished by notes, but they 
must be so placed that they may be discerned one from 
another; for, from this it is, that number is called 
discreet quantity, whereas all quantity, which is de- 
signed by motion, is called continual quantity. But 
that number may be exposed by the names of number, 
it is necessary that they be recited by heart and in 
order, as one, two, three, &c. ; for by saying one, 
one, one, and so forward, we know not what number 



90 CONCERNING BODY. 

we are at beyond two or three; which also appear to 
us in this manner not as number, but as figure. 

6. For the exposition of velocity, which, by the 
definition thereof, is a motion which, in a certain 
time, passeth over a certain space, it is requisite, not 
only that time be exposed, but that thero be also 
exposed that space which is transmitted by the body, 
whose velocity we would determine; and that a body 
be understood to be moved in that space also; so that 
there must be exposed two lines, upon one of which 
uniform motion must be understood to be made, that 
the time may be determined; and, upon the other, 

the velocity is to be computed. As if we 

A B would expose the velocity of the body A 

C D we draw two lines A B and C D, and 

place a body in C also; which done, we 

say the velocity of the body A is so great, that it 

passeth over the line A B in the same time in which 

the body C passeth over the line C D with uniform 

motion. 

7. Weight is exposed by any heavy body, of what 
matter soever, so it be always alike heavy. 

8. The proportion of two magnitudes is then ex- 
posed, when the magnitudes themselves are exposed, 
namely, the proportion of equality, when the magni- 
tudes are equal; and of inequality, when they are 
unequal. For seeing, by the 5th article of the pre- 
ceding chapter, the proportion of two unequal mag- 
nitudes consists in their difference, compared with 
either of them ; and when two unequal magnitudes are 
exposed, their difference is also exposed; it follows, 
that when magnitudes, which have proportion to one 
another, are exposed, their proportion also is ex- 
posed with them; and, in like manner, the proportion 



. A 




B 


C 




D 


, E 


G 


F 



OF QUANTITY. 91 

of equals, which consists in this, that there is no 
difference of magnitude betwixt them, is exposed at 
the same time when the equal magnitudes themselves 
are exposed. For example, if the exposed lines A B 
and C D be equal, the proportion of 
equality is exposed in them; and if the_ 
exposed lines, E F and E G be unequal, 
the proportion which E F has to E G, 
and that which E G has to E F are also 
exposed in them; for not only the lines themselves, 
but also their difference, G F, is exposed. The propor- 
tion of unequals is quantity; for the difference, G F, 
in which it consists, is quantity. But the proportion 
of equality is not quantity; because, between equals, 
there is no difference; nor is one equality greater 
than another, as one inequality is greater than another 
inequality. 

9. The proportion of two times, or of two uniform 
velocities, is then exposed, when two lines are ex- 
posed by which two bodies are understood to be moved 
uniformly; and therefore the same two lines serve 
to exhibit both their own proportion, and that of 
the times and velocities, according as they are con- 
sidered to be exposed for the magnitudes themselves, 
or for the times or velocities. For let the two 
lines A and B be exposed; their proportion A 
therefore (by the last foregoing article) is ex- B 
posed; and if they be considered as drawn with""" 
equal and uniform velocity, then, seeing their times 
are greater, or equal, or less, according as the same 
spaces are transmitted in greater, or equal, or less 
time, the lines A and B will exhibit the equality or 
inequality, that is, the proportion of the times. To 
conclude, if the same lines, A and B, be considered 



92 CONCERNING BODY. 

as drawn in the same time, then, seeing their veloci- 
ties are greater, or equal, or less, according as they 
pass over in the same time longer or equal, or shorter 
lines, the same lines, A and B, will exhibit the equality, 
or inequality, that is, the proportion of their veloci- 
ties. 

CHAPTER XIII. 

OF ANALOGISM, OR THE SAME PROPORTION. 

I, 2, 3, 4. The nature and definition of proportion, arithmet- 
ical and geometrical. — 5. The definition, and some proper- 
ties of the same arithmetical proportion. — 6, 7. The defini- 
tion and transmutations of analogism, or the same 
geometrical proportion. — 8, 9. The definitions of hyper- 
logism and hypologism, that is, of greater and less propor- 
tion, and their transmutations. — 10, 11, 12. Comparison of 
analogical quantities, according to magnitude. — 13, 14, 15. 
Composition of proportions. — 16, 17, 18, 19, 20, 21, 22, 23, 24, 

25. The definition and properties of continual proportion. — 

26, 27, 28, 29. Comparison of arithmetical and geometrical 
proportions. 

CHAPTER XIV. 

OF STRAIT AND CROOKED, ANGLE AND FIGURE. 

I. The definition and properties of a strait line. — 2. The 
definition and properties of a plane superficies. — 3. Several 
sorts of crooked lines. — 4. The definition and properties of 
a circular line. — 5. The properties of a strait line taken in a 
plane. — 6. The definition of tangent lines. — 7. The definition 
of an angle, and the kinds thereof. — 8. In concentric circles, 
arches of the same angle are to one another, as the whole 
circumferences are. — 9. The quantity of an angle, in what it 
consists. — 10. The distinction of angles, simply so called. — 



OF QUANTITY. 93 

ii. Of strait lines from the centre of a circle to a tangent of 
the same. — 12. The general definition of parallels, and the 
properties of strait parallels. — 13. The circumferences of 
circles are to one another, as their diameters are. — 14. In 
triangles, strait lines parallel to the bases are to one another, 
as the parts of the sides which they cut off from the vertex. 
— 15. By what fraction of a strait line the circumference of a 
circle is made. — 16. That an angle of contingence is quan- 
tity, but of a different kind from that of an angle simply so 
called; and that it can neither add nor take way any thing 
from the same. — 17. That the inclination of planes is angle 
simply so called. — 18. A solid angle, what it is. — 19. What 
is the nature of asymptotes. — 20. Situation, by what it is 
determined. — 21. What is like situation; what is figure; and 
what are like figures. 



PART III. 

PROPORTIONS OF MOTIONS AND 
MAGNITUDES. 

CHAPTER XV. 

OF THE NATURE, PROPERTIES, AND DIVERS CONSIDERA- 
TIONS OF MOTION AND ENDEAVOUR. 

I. Repetition of some principles of the doctrine of motion 
formerly set down. — 2. Other principles added to them. — 
3. Certain theorems concerning the nature of motion. — 4. 
Divers considerations of motion. — 5. The way by which the 
first endeavour of bodies moved tendeth. — 6. In motion 
which is made by concourse, one of the movents ceasing, 
the endeavour is made by the way by which the rest tend. — 
7. All endeavour is propagated in infinitum. — 8. How much 
greater the velocity or magnitude is of a movent, so much 
the greater is the efficacy thereof upon any other body in its 
way. 

i. The next things in order to be treated of are 
motion and magnitude, which are the most common 
accidents of all bodies. This place therefore most prop- 
erly belongs to the elements of geometry. But because 
this part of philosophy, having been improved by the 
best wits of all ages, has afforded greater plenty of 
matter than can well be thrust together within the nar- 
row limits of this discourse, I thought fit to admonish 
the reader, that before he proceeded further, he take 

95 



96 CONCERNING BODY. 

into his hands the works of Euclid, Archimedes, Apollo- 
nius, and other as well ancient as modern writers. For 
to what end is it, to do over again that which is already 
done? The little therefore that I shall say concerning 
geometry in some of the following chapters, shall be 
such only as is new, and conducing to natural phi- 
losophy. 

I have already delivered some of the principles of 
this doctrine in the eighth and ninth chapters ; which I 
shall briefly put together here, that the reader in going 
on may have their light nearer at hand. 

First, therefore, in chap, viii, art. 10, motion is de- 
fined to be the continual privation of one place, and 
acquisition of another. 

Secondly, it is there shown, that whatsoever is moved 
is moved in time. 

Thirdly, in the same chapter, art. II, I have defined 
rest to be when a body remains for some time in one 
place. 

Fourthly, it is there shown, that whatsoever is moved 
is not in any determined place; as also that the same 
has been moved, is still moved, and will yet be moved; 
so that in every part of that space, in which motion is 
made, we may consider three times, namely, the past, 
the present, and the future time. 

Fifthly, in art. 15 of the same chapter, I have defined 
velocity or swiftness to be motion considered as pozver, 
namely, that power by which a body moved may in a 
certain time transmit a certain length; which also may 
more briefly be enunciated thus, velocity is the quantity 
of motion determined by time and line. 

Sixthly, in the same chapter, art. 16, I have shown 
that motion is the measure of time. 

Seventhly, in the same chapter, art. 17, 1 have defined 



MOTION AND ENDEAVOUR. 97 

motions to be equally swift, when in equal times equal 
lengths are transmitted by them. 

Eighthly, in art. 18 of the same chapter, motions are 
defined to be equal, when the swiftness of one moved 
body, computed in every part of its magnitude, is equal 
to the swiftness of another, computed also in every part 
of its magnitude. From whence it is to be noted, that 
motions equal to one another, and motions equally 
swift, do not signify the same thing; for when two 
horses draw abreast, the motion of both is greater than 
the motion of either of them singly ; but the swiftness 
of both together is but equal to that of either. 

Ninthly, in art. 19 of the same chapter, I have shown, 
that whatsoever is at rest will always be at rest, unless 
there be some other body besides it, which by getting 
into its place suffers it no longer to remain at rest. 
And that whatsoever is moved, will always be moved, 
unless there be some other body besides it, which 
hinders its motion. 

Tenthly, in chap. IX, art. 7, I have demonstrated 
that when any body is moved which was formerly at 
rest, the immediate efficient cause of that motion is in 
some other moved and contiguous body. 

Eleventhly, I have shown in the same place, that 
whatsoever is moved, will always be moved in the 
same way, and with the same swiftness, if it be not 
hindered by some other moved and contiguous body. 

2. To which principles I shall here add those that 
follow. First, I define endeavour to be motion made 
in less space and time than can be given; that is less 
than can be determined or assigned by exposition or 
number; that is, motion made through the length of a 
point, and in an instant or point of time. For the ex- 
plaining of which definition it must be remembered, 



98 CONCERNING BODY. 

that by a point is not to be understood that which has 
no quantity, or which cannot by any means be divided ; 
for there is no such thing in nature; but that, whose 
quantity is not at all considered, that is, whereof neither 
quantity nor any part is computed in demonstration; 
so that a point is not to be taken for an indivisible, but 
for an undivided thing ; as also an instant is to be taken 
for an undivided, and not for an indivisible time. 

In like manner, endeavour is to be conceived as mo- 
tion ; but so as that neither the quantity of the time in 
which, nor of the line in which it is made, may in 
demonstration be at all brought into comparison with 
the quantity of that time, or of that line of which it is 
a part. And yet, as a point may be compared with a 
point, so one endeavour may be compared with another 
endeavour, and one may be found to be greater or less 
than another. For if the vertical points of two angles 
be compared, they will be equal or unequal in the same 
proportion which the angles themselves have to one 
another. Or if a strait line cut many circumferences of 
concentric circles, the inequality of the points of inter- 
section will be in the same proportion which the peri- 
meters have to one another. And in the same manner, 
if two motions begin and end both together, their en- 
deavours will be equal or unequal, according to the 
proportion of their velocities ; as we see a bullet of lead 
descend with greater endeavour than a ball of wool. 

Secondly, I define impetus, or quickness of motion, 
to be the swiftness or velocity of the body moved, but 
considered in the several points of that time in which 
it is moved. In which sense impetus is nothing else 
but the quantity or velocity of endeavour. But con- 
sidered with the whole time, it is the whole velocity of 
the body moved taken together throughout all the time, 



MOTION AND ENDEAVOUR. 99 

and equal to the product of a line representing the 
time, multiplied into a line representing the arithmet- 
ically mean impetus or quickness. Which arithmet- 
ical mean, what it is, is defined in the 29th article of 
chapter xm. 

And because in equal times the ways that are passed 
are as the velocities, and the impetus is the velocity 
they go withal, reckoned in all the several points of the 
times, it followeth that during any time whatsoever, 
howsoever the impetus be increased or decreased, the 
length of the way passed over shall be increased or 
decreased in the same proportion; and the same line 
shall represent both the way of the body moved, and 
the several impetus or degrees of swiftness wherewith 
the way is passed over. 

And if the body moved be not a point, but a strait 

line moved so as that every point thereof make a 

several strait line, the plane described by its motion, 

whether uniform, accelerated, or retarded, shall be 

greater or less, the time being the same, in the same 

proportion with that of the impetus reckoned in one 

motion to the impetus reckoned in the other. For the 

reason is the same in parallelograms and their sides. 
********* 

Thirdly, I define resistance to be the endeavour of 
one moved body either wholly or in part contrary to 
the endeavour of another moved body, which toucheth 
the same. I say, wholly contrary, when the endeavour 
of two bodies proceeds in the same strait line from the 
opposite extremes, and contrary in part, when two 
bodies have their endeavour in two lines, which, pro- 
ceeding from the extreme points of a strait line, meet 
without the same. 

Fourthly, that I may define what it is to press, I say, 

LofC. 



ioo CONCERNING BODY. 

that of two moved bodies one presses the other, when 
with its endeavour it makes either all or fart of the 
other body to go out of its place. 

Fifthly, a body which is pressed and not wholly 
removed, is said to restore itself, when, the pressing 
body being taken away, the parts which were moved do, 
by reason of the internal constitution of the pressed 
body, return every one into its own place. And this 
we may observe in springs, in blown bladders, and in 
many other bodies, whose parts yield more or less to the 
endeavour which the pressing body makes at the first 
arrival ; but afterwards, when the pressing body is re- 
moved, they do, by some force within them, restore 
themselves, and give their whole body the same figure 
it had before. 

Sixthly, I define force to be the impetus or quickness 
of motion multiplied either into itself, or into the mag- 
nitude of the movent, by means whereof the said 
movent works more or less upon the body that re- 
sists it. 

3. Having premised thus much, I shall now demon- 
strate, first, that if a point moved come to touch another 
point which is at rest, how little soever the impetus or 
quickness of its motion be, it shall move that other 
point. For if by that impetus it do not at all move it 
out of its place, neither shall it move it with double the 
same impetus. For nothing doubled is still nothing; 
and for the same reason it shall never move it with that 
impetus, how many times soever it be multiplied, be- 
cause nothing, however it be multiplied, will for ever 
be nothing. Wherefore, when a point is at rest, if it do 
not yield to the least impetus, it will yield to none ; and 
consequently it will be impossible that that, which is at 
rest, should ever be moved. 



MOTION AND ENDEAVOUR. 101 

Secondly, that when a point moved, how little soever 
the impetus thereof be, falls upon a point of any body 
at rest, how hard soever that body be, it will at the first 
touch make it yield a little. For if it do not yield to the 
impetus which is in that point, neither will it yield to 
the impetus of never so many points, which have all 
their impetus severally equal to the impetus of that 
point. For seeing all those points together work 
equally, if any one of them have no effect, the aggre- 
gate of them all together shall have no effect as many 
times told as there are points in the whole body, that is, 
still no effect at all; and by consequent there would 
be some bodies so hard that it would be impossible to 
break them ; that is, a finite hardness, or a finite force, 
would not yield to that which is infinite; which is 
absurd. 

Coroll. It is therefore manifest, that rest does noth- 
ing at all, nor is of any efficacy ; and that nothing but 
motion gives motion to such things as be at rest, and 
takes it from things moved. 

Thirdly, that cessation in the movent does not 
cause cessation in that which was moved by it. For 
(by number n of art. I of this chapter) whatsoever is 
moved perseveres in the same way and with the same 
swiftness, as long as it is not hindered by something 
that is moved against it. Xow it is manifest, that cessa- 
tion is not contrary motion; and therefore it follows 
that the standing still of the movent does not make it 
necessary that the thing moved should also stand still. 

Coroll. They are therefore deceived, that reckon the 
taking away of the impediment or resistance for one 
of the causes of motion. 

4. Motion is brought into account for divers re- 
spects ; first, as in a body undivided, that is, considered 



102 CONCERNING BODY. 

as a point ; or, as in a divided body. In an undivided 
body, when we suppose the way, by which the motion 
is made, to be a line ; and in a divided body, when we 
compute the motion of the several parts of that body, 
as of parts. 

Secondly, from the diversity of the regulation of 
motion, it is in body, considered as undivided, some- 
times uniform and sometimes multiform. Uniform 
is that by which equal lines are always transmitted in 
equal times ; and multiform, when in one time more, in 
another time less space is transmitted. Again, of multi- 
form motions, there are some in which the degrees of 
acceleration and retardation proceed in the same 
proportions, which the spaces transmitted have, whether 
duplicate, or triplicate, or by whatsoever number mul- 
tiplied ; and others in which it is otherwise. 

Thirdly, from the number of the movents; that is, 
one motion is made by one movent only, and another 
by the concourse of many movents. 

Fourthly, from the position of that line in which a 
body is moved, in respect of some other line ; and from 
hence one motion is called perpendicular, another ob- 
lique, another parallel. 

Fifthly, from the position of the movent in re- 
spect of the moved body ; from whence one motion is 
pulsion or driving, another traction or drawing. Pul- 
sion, when the movent makes the moved body go be- 
fore it; and traction, when it makes it follow. Again 
there are. two sorts of pulsion; one, when the motions 
of the movent and moved body begin both together, 
which may be called the trusion or thrusting and vec- 
tion; the other, when the movent is first moved, and 
afterwards the moved body, which motion is called 
percussion or stroke. 



MOTION AND ENDEAVOUR. 103 

Sixthly, motion is considered sometimes from the 
effect only which the movent works in the moved 
body, which is usually called moment. Now moment 
is the excess of motion which the movent has above 
the motion or endeavour of the resisting body. 

Seventhly, it may be considered from the diversity 
of the medium; as one motion may be made in vacuity 
or empty place; another in a fluid; another in a con- 
sistent medium, that is, a medium whose parts are by 
some power so consistent and cohering, that no part 
of the same will yield to the movent, unless the whole 
yield also. 

Eighthly, when a moved body is considered as having 
parts, there arises another distinction of motion into 
simple and compound. Simple, when all the several 
parts describe several equal lines; compounded, when 
the lines described are unequal. 

5. All endeavour tends towards that part, that is 
to say, in that way which is determined by the motion 
of the movent, if the movent be but one; or, if there 
be many movents, in that way which their concourse 
determines. For example, if a moved body have direct 
motion, its first endeavour will be in a strait line ; if it 
have circular motion, its first endeavour will be in the 
circumference of a circle. 

6. And whatsoever the line be, in which a body has 
its motion from the concourse of two movents, as soon 
as in any point thereof the force of one of the movents 
ceases, there immediately the former endeavour of that 
body will be changed into an endeavour in the line of 
the other movent. 

Wherefore, when any body is carried on by the con- 
course of two winds, one of those winds ceasing, the 
endeavour and motion of that body will be in that line, 



104 CONCERNING BODY. 

in which it would have been carried by that wind alone 
which blows still. And in the describing of a circle, 
where that which is moved has its motion determined 
by a movent in a tangent, and by the radius which 
keeps it in a certain distance from the centre, if the 
retention of the radius cease, that endeavour, which was 
in the circumference of the circle, will now be in the 
tangent, that is, in a strait line. For, seeing endeavour 
is computed in a less part of the circumference than can 
be given, that is, in a point, the way by which a body 
is moved in the circumference is compounded of in- 
numerable strait lines, of which every one is less than 
can be given ; which are therefore called points. Where- 
fore when any body, which is moved in the circum- 
ference of a circle, is freed from the retention of the 
radius, it will proceed in one of those strait lines, that 
is, in a tangent. 

7. All endeavour, whether strong or weak, is propa-. 
gated to infinite distance ; for it is motion. If therefore 
the first endeavour of a body be made in space which 
is empty, it will always proceed with the same velocity ; 
for it cannot be supposed that it can receive any re- 
sistance at all from empty space ; and therefore, (by art. 
7, chap, ix ) will always proceed in the same way and 
with the same swiftness. And if its endeavour be in 
space which is filled, yet, seeing endeavour is mo- 
tion, that which stands next in its way shall be removed, 
and endeavour further, and again remove that which 
stands next, and so infinitely. Wherefore the propa- 
gation of endeavour, from one part of full space to 
another, proceeds infinitely. Besides, it reaches in any 
instant to any distance, how great soever. For in the 
same instant in which the first part of the full medium 
removes that which is next it, the second also removes 



MOTION AND ENDEAVOUR. 105 

that part which is next to it ; and therefore all endeav- 
our, whether it be in empty or in full space, proceeds 
not only to any distance, how great soever, but also in 
any time, how little soever, that is, in an instant. Nor 
makes it any matter, that endeavour, by proceeding, 
grows weaker and weaker, till at last it can no longer 
be perceived by sense; for motion may be insensible; 
and I do not here examine things by sense and experi- 
ence, but by reason. 

8. When two movents are of equal magnitude, 
the swifter of them works with greater force than the 
slower, upon a body that resists their motion. Also, 
if two movents have equal velocity, the greater of 
them works with more force than the less. For where 
the magnitude is equal, the movent of greater ve- 
locity makes the greater impression upon that body 
upon which it falls ; and where the velocity is equal, 
the movent of greater magnitude falling upon the 
same point, or an equal part of another body, loses less 
of its velocity, because the resisting body works only 
upon that part of the movent which it touches, and 
therefore abates the impetus of that part only ; whereas 
in the mean time the parts, which are not touched, pro- 
ceed, and retain their whole force, till they also come 
to be touched ; and their force has some effect. Where- 
fore, for example, in batteries a longer than a shorter 
piece of timber of the same thickness and velocitcy, and 
a thicker than a slenderer piece of the same length and 
velocity, work a greater effect upon the wall. 



106 CONCERNING BODY. 

CHAPTER XVI. 

OF MOTION ACCELERATED AND UNIFORM, AND OF 
MOTION BY CONCOURSE. 

I. The velocity of any body, in what time soever it be com- 
puted, is that which is made of the multiplication of the 
impetus, or quickness of its motion into the time. — 2-5. In 
all motiQn, the lengths which are passed through are to one 
another, as the products made by the impetus multiplied into 

■ the time. — 6. If two bodies be moved with uniform motion 
through two lengths, the proportion of those lengths to one 
another will be compounded of the proportions of time to 
time, and impetus to impetus, directly taken. — 7. If two 
bodies pass through two lengths with uniform motion, the 
proportion of their time to one another will be compounded 
of the proportions of length to length, and impetus to impe- 
tus reciprocally taken ; also the proportion of their impetus 
to one another will be compounded of the proportions of 
length to length, and time to time reciprocally taken. — 8. If 
a body be carried on with uniform motion by two movents 
together, which meet in an angle, the line by which it passes 
will be a strait line, subtending the complement of that 
angle to two right angles. — 9, &c. If a body be carried by 
two movents together, one of them being moved with uni- 
form, the other with accelerated motion, and the proportion 
of their lengths to their times being explicable in numbers, 
how to find out what line that body describes. 

CHAPTER XVII. 

OF FIGURES DEFICIENT. 

I. Definitions of a deficient figure; of a complete figure; of the 
complement of a deficient figure; and of proportions which 
are proportional and commensurable to one another. — 2. The 
proportion of a deficient figure to its complement. — 3. The 
proportions of deficient figures to the parallelograms in 



CONCERNING BODY. 107 

which they are described, set forth in a table. — 4. The de- 
scription and production of the same figures. — 5. The draw- 
ing of tangents to them. — 6. In what proportion the same 
figures exceed a strait-lined triangle of the same altitude 
and base. — 7. A table of solid deficient figures described in 
a cylinder. — 8. In what proportion the same figures exceed 
a cone of the same altitude and base. — 9. How a plain defi- 
cient figure may be described in a parallelogram, so that it 
be to a triangle of the same base and altitude, as another 
deficient figure, plain or solid, twice taken, is to the same 
deficient figure, together with the complete figure in which it 
is described. — 10. The transferring of certain properties of 
deficient figures described in a parallelogram to the propor- 
tions of the spaces transmitted with several degrees of veloc- 
ity. — II. Of deficient figures described in a circle. — 12. The 
proposition demonstrated in art. 2 confirmed from the ele- 
ments of philosophy. — 13. An unusual way of reasoning 
concerning the equality between the superficies of a portion 
of a sphere and a circle. — 14. How from the description of 
deficient figures in a parallelogram, any number of mean 
proportionals may be found out between two given strait 
lines. 

CHAPTER XVIII. 

OF THE EQUATION OF STRAIT LINES WITH THE 
CROOKED LINES OF PARABOLAS AND OTHER FIGURES 
MADE IN IMITATION OF PARABOLAS. 

I. To find the strait line equal to the crooked line of a semi- 
parabola. — 2. To find a strait line equal to the crooked line of 
the first semiparabolaster, or to the crooked line of any other 
of the deficient figures of the table of the 3d article of the 
precedent chapter. 



io8 



CONCERNING BODY. 
CHAPTER XIX. 



OF ANGLES OF INCIDENCE AND REFLECTION, EQUAL 
BY SUPPOSITION. 



I. If two strait lines falling upon another strait line be parallel, 
the lines reflected from them shall also be parallel. — 2. If 
two strait lines drawn from one point fall upon another 
strait line, the lines reflected from them, if they be drawn out 
the other way, will meet in an angle equal to the angle made 
by the lines of incidence. — 3. If two strait parallel lines, 
drawn not oppositely, but from the same parts, fall upon the 
circumference of a circle, the lines reflected from them, if 
produced they meet within the circle, will make an angle 
double to that which is made by two strait lines drawn from 
the centre to the points of incidence. — 4. If two strait lines 
drawn from the same point without a circle fall upon the 
circumference, and the lines reflected from them being pro- 
duced meet within the circle, they will make an angle equal 
to twice that angle, which is made by two strait lines drawn 
from the centre to the points of incidence, together with the 
angle which the incident lines themselves make. — 5. If two 
strait lines drawn from one point fall upon the concave cir- 
cumference of a circle, and the angle they make be less than 
twice the angle at the centre, the lines reflected from them and 
meeting within the circle will make an angle, which being 
added to the angle of the incident lines will be equal to 
twice the angle at the centre. — 6. If through any one point 
two unequal chords be drawn cutting one another, and the 
centre of the circle be not placed between them, and the 
lines reflected from them concur wheresoever, there cannot 
through the point, through which the two former lines were 
drawn, be drawn any other strait line whose reflected line 
shall pass through the common point of the two former 
lines reflected. — 7. In equal chords the same is not true. — 
8. Two points being given in the circumference of a circle, to 
draw two strait lines to them, so that their reflected lines 
may contain any angle given. — 9. If a strait line falling upon 
the circumference of a circle be produced till it reach the 



CONCERNING BODY. 109 

semidiameter, and that part of it, which is intercepted be- 
tween the circumference and the semidiameter, be equal to 
that part of the semidiameter which is between the point of 
concourse and the centre, the reflected line will be parallel 
to the semidiameter. — 10. If from a point within a circle, 
two strait lines be drawn to the circumference, and their 
reflected lines meet in the circumference of the same circle, 
the angle made by the reflected lines will be a third part of 
the angle made by the incident lines. 

CHAPTER XX. 



OF THE DIMENSION OF A CIRCLE, AND THE DIVISION 
OF ANGLES OR ARCHES. 

I. The dimension of a circle never determined in numbers by 
Archimedes and others. — 2. The first attempt for the finding 
out of the dimension of a circle by lines. — 3. The second 
attempt for the finding out of the dimension of a circle from 
the consideration of the nature of crookedness. — 4. The third 
attempt ; and some things propounded to be further searched 
into. — 5. The equation of the spiral of Archimedes with a 
strait line. — 6. Of the analysis of geometricians by the pow- 



ers of lines. 



CHAPTER XXI. 



OF CIRCULAR MOTION. 



I. In simple motion, every strait line taken in the body moved 
is so carried, that it is always parallel to the places in which 
it formerly was. — 2. If circular motion be made about a rest- 
ing centre, and in that circle there be an epicycle, whose 
revolution is made the contrary way, in such manner that in 
equal times it make equal angles, every strait line taken in 
that epicycle will be so carried, that it will always be par- 
allel to the places in which it formerly was. — 3. The prop- 
erties of simple motion.— 4. If a fluid be moved with simple 



no CONCERNING BODY. 

circular motion, all the points taken in it will describe their 
circles in times proportional to the distances from the cen- 
tre. — 5. Simple motion dissipates heterogeneous and con- 
gregates homogeneous bodies. — 6. If a circle made by a 
movent moved with simple motion be commensurable to 
another circle made by a point which is carried about by 
the same movent, all the points of both the circles will at 
some time return to the same situation. — 7. If a sphere have 
simple motion, its motion will more dissipate heterogeneous 
bodies by how much it is more remote from the poles. — 8. 
If the simple circular motion of a fluid body be hindered by 
a body which is not fluid, the fluid body will spread itself 
upon the superficies of that body. — 9. Circular motion about 
a fixed centre casteth off by the tangent such things as lie 
upon the circumference and stick not to it. — 10. Such things, 
as are moved with simple circular motion, beget simple cir- 
cular motion. — 11. If that which is so moved have one side 
hard and the other side fluid, its motion will not be per- 
fectly circular. 

CHAPTER XXII. 



OF OTHER VARIETY OF MOTION. 

I. Endeavour and pressure how they differ. — 2. Two kinds of 
mediums in which bodies are moved. — 3. Propagation of 
motion, what it is. — 4. What motion bodies have, when they 
press one another. — 5. Fluid bodies, when they are pressed 
together, penetrate one another. — 6. When one body presseth 
another and doth not penetrate it, the action of the pressing 
body is perpendicular to the superficies of the body pressed. — 
7. When a hard body, pressing another body, penetrates the 
same, it doth not penetrate it perpendicularly, unless it fall 
perpendicularly upon it. — 8. Motion sometimes opposite to 
that of the movent. — 9. In a full medium, motion is propa- 
gated to any distance. — 10. Dilatation and contraction what 
they are. — n. Dilatation and contraction suppose mutation 
of the smallest parts in respect of their situation. — 12. All 
traction is pulsion. — 13. Such things as being pressed or 
bent restore themselves, have motion in their internal parts. — 



CONCERNING BODY. in 

14. Though that which carrieth another be stopped, the body- 
carried will proceed. — 15, 16. The effects of percussion not 
to be compared with those of weight. — 17, 18. Motion can- 
not begin first in the internal parts of the body. — 19. Action 
and reaction proceed in the same line. — 20. Habit, what it is. 

CHAPTER XXIII. 

OF THE CENTRE OF EQUIPONDERATION ; OF BODIES 
PRESSING DOWNWARDS IN STRAIT PARALLEL LINES. 

I. Definitions and suppositions. — 2. Two planes of equiponder- 
ation are not parallel. — 3. The centre of equiponderation is 
in every plane of equiponderation. — 4. The moments of equal 
ponderants are to one another as their distances from the 
centre of the scale. — 5, 6.. The moments of unequal ponder- 
ants have their proportion to one another compounded 
of the proportions of their weights and distances from the 
centre of the scale. — 7. If two ponderants have their weights 
and distances from the centre of the scale in reciprocal pro- 
portion, they are equally poised; and contrarily. — 8. If the 
parts of any ponderant press the beams of the scale every- 
where equally, all the parts cut off, reckoned from the cen- 
tre of the scale, will have their moments in the same pro- 
portion with that of the parts of a triangle cut off from the 
vertex by strait lines parallel to the base. — 9. The diameter 
of equiponderation of figures, which are deficient according 
to commensurable proportions of their altitudes and bases, 
divides the axis, so that the part taken next the vertex is to 
the other part of the complete figure to the deficient figure. — 
10. The diameter of equiponderation of the complement of 
the half of any of the said deficient figures, divides that line 
which is drawn through the vertex parallel to the base, so 
that the part next the vertex is to the other part of the com- 
plete figure to the complement. — II. The centre of equi- 
ponderation of the half of any of the deficient figures in the 
first row of the table of art. 3, chap, xvii, may be found out 
by the numbers of the second row. — 12. The centre of equi- 
ponderation of the half of any of the figures of the second 



112 CONCERNING BODY. 

row of the same table, may be found out by the numbers of 
the fourth row. — 13. The centre of equiponderation of the 
half of any of the figures in the same table being known, the 
centre of the excess of the same figure above a triangle of 
the same altitude and base is also known. — 14. The centre of 
equiponderation of a solid sector is in the axis so divided, 
that the part next the vertex be to the whole axis, wanting 
half the axis of the portion of the sphere, as 3 to 4. 

CHAPTER XXIV. 

OF REFRACTION AND REFLECTION. 

I. Definitions. — 2. In perpendicular motion there is no refrac- 
tion. — 3. Things thrown out of a thinner into a thicker me- 
dium are so refracted that the angle refracted is greater than 
the angle of inclination. — 4. Endeavour, which from one 
point tendeth every way, will be so refracted, as that the 
sine of the angle refracted will be to the sine of the angle of 
inclination, as the density of the first medium is to the 
density of the second medium, reciprocally taken. — 5. The 
sine of the refracted angle in one inclination is to the sine 
of the refracted angle in another inclination, as the sine of 
the angle of that inclination is to the sine of the angle of 
this inclination. — 6. If two lines of incidence, having equal 
inclination, be the one in a thinner, the other in a thicker 
medium, the sine of the angle of inclination will be a mean 
proportional between the two sines of the refracted angles. — 

7. If the angle of inclination be semirect, and the line of in- 
clination be in the thicker medium, and the proportion of 
their densities be the same with that of the diagonal to the 
side of a square, and the separating superficies be plane, 
the refracted line will be in the separating superficies. — 

8. If a body be carried in a strait line upon another body, 
and do not penetrate the same, but be reflected from it, the 
angle of reflection will be equal to the angle of incidence. — 

9. The same happens in the generation of motion in the line 
of incidence. 



PART IV. 

PHYSICS, OR THE PHENOMENA 
OF NATURE. 

CHAPTER XXV.* 

OF SENSE AND ANIMAL MOTION. 

I. The connexion of what hath been said with that which fol- 
loweth. — 2. The investigation of the nature of sense, and the 
definition of sense. — 3. The subject and object of sense.— 
4. The organs of sense. — 5. All bodies are not indued with 
sense. — 6. But one phantasm at one and the same time. — 
7. Imagination the remains of past sense, which also is 
memory. Of sleep. — 8. How phantasms succeed one an- 
other. — 9. Dreams, whence they proceed. — 10. Of the senses, 
their kinds, their organs, and phantasms proper and com- 
mon. — 11. The magnitude of images, how and by what it is 
determined. — 12. Pleasure, pain, appetite and aversion, what 
they are. — 13. Deliberation and will, what. 

I. I have, in the first chapter, defined philosophy 
to be knowledge of effects acquired by true ratiocination, 
from knowledge first had of their causes and gen- 
eration; and of such causes or generations as may be, 
from former knowledge of their effects or appear- 
ances. There are, therefore, two methods of philoso- 
phy; one, from the generation of things to their 
possible effects ; and the other, from their effects or ap- 

* For list of the writings of Hobbes on psychology, cf. p. xx. 
113 



H4 CONCERNING BODY. 

pearances to some possible generation of the same. In 
the former of these the truth of the first principles of 
our ratiocination, namely definitions, is made and con- 
stituted by ourselves, whilst we consent and agree 
about the appellations of things. And this part I have 
finished in the foregoing chapters; in which, if I am 
not deceived, I have affirmed nothing, saving the defi- 
nitions themselves, which hath not good coherence 
with the definitions I have given ; that is to say, which 
is not sufficiently demonstrated to all those, that agree 
with me in the use of words and appellations ; for whose 
sake only I have written the same. I now enter upon 
the other part ; which is the finding out by the appear- 
ances or effects of nature, which we know by sense, 
some ways and means by which they may be, I do not 
say they are, generated. The principles, therefore, 
upon which the following discourse depends, are not 
such as we ourselves make and pronounce in general 
terms, as definitions ; but such, as being placed in the 
things themselves by the Author of Nature, are by us 
observed in them ; and we make use of them in single 
and particular, not universal propositions. Nor do 
they impose upon us any necessity of constituting 
theorems ; their use being only, though not without such 
general propositions as have been already demonstrated, 
to show us the possibility of some production or gen- 
eration. Seeing, therefore, the science, which is here 
taught, hath its principles in the appearances of nature, 
and endeth in the attaining of some knowledge of 
natural causes, I have given to this part the title of 
Physics, or the Phenomena of Nature. Now such 
things as appear, or are shown to us by nature, we call 
phenomena or appearances. 

Of all the phenomena or appearances which are 



OF SENSE AND ANIMAL MOTION. 115 

near us, the most admirable is apparition itself, 
to <jxuv€(T6ai; namely, that some natural bodies have 
in themselves the patterns almost of all things, and 
others of none at all. So that if the appearances be 
the principles by which we know all other things, 
we must needs acknowledge sense to be the principle 
by which we know those principles, and that all the 
knowledge we have is derived from it. And as for 
the causes of sense, we cannot begin our search of 
them from any other phenomenon than that of sense 
itself. But you will say, by what sense shall we take 
notice of sense? I answer, by sense itself, namely, by 
the memory which for some time remains in us of 
things sensible, though they themselves pass away. For 
he that perceives that he hath perceived, remembers. 

In the first place, therefore, the causes of our per- 
ception, that is, the causes of those ideas and phan- 
tasms which are perpetually generated within us whilst 
we make use of our senses, are to be enquired into; 
and in what manner their generation proceeds. To 
help which inquisition, we may observe first of all, that 
our phantasms or ideas are not always the same; but 
that new ones appear to us, and old ones vanish, ac- 
cording as we apply our organs of sense, now to one 
object, now to another. Wherefore they are generated, 
and perish. And from hence it is manifest, that they 
are some change or mutation in the sentient. 

2. Now that all mutation or alteration is motion 
or endeavour (and endeavour also is motion) in the 
internal parts of the thing that is altered, hath been 
proved (in art. 9, chap, vm) from this, that whilst 
even the least parts of any body remain in the same 
situation in respect of one another, it cannot be said 
that any alteration, unless perhaps that the whole body 



u6 CONCERNING BODY. 

together hath been moved, hath happened to it ; but that 
it both appeareth and is the same it appeared and was 
before. Sense, therefore, in the sentient, can be noth- 
ing else but motion in some of the internal parts of 
the sentient; and the parts so moved are parts of the 
organs of sense. For the parts of our body, by which 
we perceive any thing, are those we commonly call the 
organs of sense. And so we find what is the subject of 
our sense, namely, that in which are the phantasms; 
and partly also we have discovered the nature of sense, 
namely, that it is some internal motion in the sentient. 

I have shown besides (in chap, ix, art. 7) that no 
motion is generated but by a body contiguous and 
moved : from whence it is manifest, that the immediate 
cause of sense or perception consists in this, that the 
first organ of sense is touched and pressed. For when 
the uttermost part of the organ is pressed, it no sooner 
yields, but the part next within it is pressed also ; and, 
in this manner, the pressure or motion is propagated 
through all the parts of the organ to the innermost. 
And thus also the pressure of the uttermost part pro- 
ceeds from the pressure of some more remote body, and 
so continually, till we come to that from which, as 
from its fountain, we derive the phantasm or idea that 
is made in us by our sense. And this, whatsoever it 
be, is that we commonly call the object. Sense, there- 
fore, is some internal motion in the sentient, generated 
by some internal motion of the parts of the object, and 
propagated through all the media to the innermost part 
of the organ. By which words I have almost defined 
what sense is. 

Moreover, I have shown (art. 2, chap, xv) that all 
resistance is endeavour opposite to another endeavour, 
that is to say, reaction. Seeing, therefore, there is in 



OF SENSE AND ANIMAL MOTION. 117 

the whole organ, by reason of it own internal natural 
motion, some resistance or reaction against the motion 
which is propagated from the object to the innermost 
part of the organ, there is also in the same organ an 
endeavour opposite to the endeavour which proceeds 
from the object; so that when that endeavour inwards 
is the last action in the act of sense, then from the re- 
action, how little soever the duration of it be, a phan- 
tasm or idea hath its being ; which, by reason that the 
endeavour is now outwards, doth always appear as 
something situate without the organ. So that now I 
shall give you the whole definition of sense, as it is 
drawn from the explication of the causes thereof and 
the order of its generation, thus : sense is a phantasm, 
made by the reaction and endeavour outwards in the 
organ of sense, caused by an endeavour inwards from 
the object, remaining for some time more or less. 
_ 3. The subject of sense is the sentient itself, namely, 
some living creature; and we speak more correctly, 
when we say a living creature seeth, than when we 
say the eye seeth. The object is the thing received; 
and it is more accurately said, that we see the sun, 
than that we see the light. For light and colour, and 
heat and sound, and other qualities which are common- 
ly called sensible, are not objects, but phantasms in the 
sentients. For a phantasm is the act of sense, and dif- 
fers no otherwise from sense than fieri, that is, being a 
doing, differs from factum esse, that is, being done; 
which difference, in things that are done in an instant, 
is none at all ; and a phantasm is made in an instant. 
For in all motion which proceeds by perpetual propa- 
gation, the first part being moved moves the second, 
the second the third, and so on to the last, and that 
to any distance, how great soever. And in what 



n8 CONCERNING BODY. 

point of time the first or foremost part proceeded to 
the place of the second, which is thrust on, in the same 
point of time the last save one proceeded into 
the place of the last yielding part; which by reaction, 
in the same instant, if the reaction be strong enough, 
makes a phantasm ; and a phantasm being made, per- 
ception is made together with it. 

4. The organs of sense, which are in the sentient, 
are such parts thereof, that if they be hurt, the very 
generation of phantasms is thereby destroyed, though 
all the rest of the parts remain entire. Now these parts 
in the most of living creatures are found to be certain 
spirits and membranes, which, proceeding from the 
pia mater, involve the brain and all the nerves ; also the 
brain itself, and the arteries which are in the brain; 
and such other parts, as being stirred, the heart also, 
which is the fountain of all sense, is stirred together 
with them. For whensoever the action of the object 
reacheth the body of the sentient, that action is by 
some nerve propagated to the brain ; and if the nerve 
leading thither be so hurt or obstructed, that the motion 
can be propagated no further, no sense follows. Also 
if the motion be intercepted between the brain and the 
heart by the defect of the organ by which the action is 
proagated, there will be no perception of the object. 

5. But though all sense, as I have said, be made by 
reaction, nevertheless it is not necessary that every thing 
that reacteth should have sense. I know there have 
been philosophers, and those learned men, who have 
maintained that all bodies are endued with sense. Nor 
do I see how they can be refuted, if the nature of sense 
be placed in reaction only. And, though by the reac- 
tion of bodies inanimate a phantasm might be made, it 
would nevertheless cease, as soon as ever the object 



OF SENSE AND ANIMAL MOTION. 119 

were removed. For unless those bodies had organs, as 
living creatures have, fit for the retaining of such mo- 
tion as is made in them, their sense would be such, as 
that they should never remember the same. And 
therefore this hath nothing to do with that sense which 
is the subject of my discourse. For by sense, we com- 
monly understand the judgment we make of objects by 
their phantasms; namely, by comparing and distin- 
guishing those phantasms ; which we could never do, if 
that motion in the organ, by which the phantasm is 
made, did not remain there for some time, and make 
the same phantasm return. Wherefore sense, as I here 
understand it, and which is commonly so called, hath 
necessarily some memory adhering to it, by which 
former and later phantasms may be compared together, 
and distinguished from one another. 

Sense, therefore, properly so called, must necessarily 
have in it a perpetual variety of phantasms, that they 
may be discerned one from another. For if we should 
suppose a man to be made with clear eyes, and all the 
rest of his organs of sight well disposed, but endued 
with no other sense ; and that he should look only upon 
one thing, which is always of the same colour and 
figure, without the least appearance of variety, he would 
seem to me, whatsoever others may say, to see, no more 
than I seem to myself to feel the bones of my own 
limbs by my organs of feeling ; and yet those bones are 
always and on all sides touched by a most sensible 
membrane. I might perhaps say he were astonished, 
and looked upon it; but I should not say he saw it; 
it being almost all one for a man to be always sensible 
of one and the same thing, and not to be sensible at all 
of any thing. 

6. And yet such is the nature of sense, that it does 



120 CONCERNING BODY. 

not permit a man to discern many things at once. For 
seeing the nature of sense consists in motion; as long 
as the organs are employed about one object, they 
cannot be so moved by another at the same time, as to 
make by both their motions one sincere phantasm of 
each of them at once. And therefore two several 
phantasms will not be made by two objects working 
together, but only one phantasm compounded from the 
action of both. 

Besides, as when we divide a body, we divide its 
place; and when we reckon many bodies, we must 
necessarily reckon as many places; and contrarily, as 
I have shown in the seventh chapter ; so what number 
soever we say there be at times, we must understand 
the same number of motions also; and as oft as we 
count many motions, so oft we reckon many times. 
For though the object we look upon be of divers 
colours, yet with those divers colours it is but one 
varied object, and not variety of objects. 

Moreover, whilst those organs which are common 
to all the senses, such as are those parts of every organ 
which proceed in men from the root of the nerves to the 
heart, are vehemently stirred by a strong action from 
some one object, they are, by reason of the contumacy 
which the motion, they have already, gives them against 
the reception of all other motion, made the less fit to 
receive any other impression from whatsoever other 
objects, to what sense soever those objects belong. 
And hence it is, that an earnest studying of one object, 
takes away the sense of all other objects for the 
present. For study is nothing else but a possession of 
the mind, that is to say, a vehement motion made by 
some one object in the organs of sense, which are 
stupid to all other motions as long as this lasteth ; ac- 



OF SENSE AND ANIMAL MOTION. 121 

cording to what was said by Terence, u Populus studio 
stupidus in funambulo animum occuparat." For what 
is stupor but that which the Greeks called dvcuo-^o-ta, 
that, is, a cessation from the sense of other things? 
Wherefore at one and the same time, we cannot by 
sense perceive more than one single object; as in read- 
ing, we see the letters successively one by one, and not 
all together, though the whole page be presented to our 
eye ; and though every several letter be distinctly writ- 
ten there, yet when we look upon the whole page at 
once, we read nothing. 

From hence it is manifest, that every endeavour of 
the organ outwards, is not to be called sense, but that 
only, which at several times is by vehemence made 
stronger and more predominate than the rest; which 
deprives us of the sense of other phantasms, no other- 
wise than the sun deprives the rest of the stars of light 
not by hindering their action, but by obscuring and 
hiding them with his excess of brightness. 

7. But the motion of the organ, by which a phan- 
tasm is made, is not commonly called sense, except the 
object be present. And the phantasm remaining after 
the object is removed or past by, is called fancy, and 
in Latin imaginatio; which word, because all phantasms 
are not images, doth not fully answer the signification 
of the word fancy in its general acceptation. Never- 
theless I may use it safely enough, by understanding 
it for the Greek Qam-ao-ia. 

Imagination therefore is nothing else but sense de- 
caying, or weakened, by the absence of the object. But 
what may be the cause of this decay or weakening? 
Is the motion the weaker, because the object is taken 
away? If it were, then phantasms would always and 
necessarily be less clear in the imagination, than they 



122 CONCERNING BODY. 

are in sense ; which is not true. For in dreams, which 
are the imaginations of those that sleep, they are no 
less clear than in sense itself. But the reason why in 
men waking the phantasms of things past are more 
obscure than those of things present, is this, that their 
organs being at the same time moved by other present 
objects, those phantasms are the less predominate. 
Whereas in sleep, the passages being shut up, external 
action doth not at all disturb or hinder internal motion. 

If this be true, the next thing to be considered, will 
be, whether any cause may be found out, from the sup- 
position whereof it will follow, that the passage is shut 
up from the external objects of sense to the internal 
organ. I suppose, therefore, that by the continual ac- 
tion of objects, to which a reaction of the organ, and 
more especially of the spirits, is necessarily consequent, 
the organ is wearied, that is, its parts are no longer 
moved by the spirits without some pain; and conse- 
quently the nerves being abandoned and grown slack, 
they retire to their fountain, which is the cavity either 
of the brain or of the heart ; by which means the action 
which proceeded by the nerves is necessarily inter- 
cepted. For action upon a patient, that retires from it, 
makes but little impression at the first; and at last, 
when the nerves are by little and little slackened, none 
at all. And therefore there is no more reaction, that is, 
no more sense, till the organ being refreshed by rest, 
and by a supply of new spirits recovering strength and 
motion, the sentient awaketh. And thus it seems to be 
always, unless some other preternatural cause inter- 
vene; as heat in the internal parts from lassitude, or 
from some disease stirring the spirits and other parts 
of the organ in some extraordinary manner. 

8. Now it is not without cause, nor so casual a 



OF SENSE AND ANIMAL MOTION. 123 

thing as many perhaps think it, that phantasms in this 
their great variety proceed from one another ; and that 
the same phantasms sometimes bring into the mind 
other phantasms like themselves, and at other times 
extremely unlike. For in the motion of any continued 
body, one part follows another by cohesion ; and there- 
fore, whilst we turn our eyes and other organs succes- 
sively to many objects, the motion which was made by 
every one of them remaining, the phantasms are re- 
newed as often as any one of those motions comes to 
be predominant above the rest; and they become pre- 
dominant in the same order in which at any time 
formerly they were generated by sense. So that when 
by length of time very many phantasms have been gen- 
erated within us by sense, then almost any thought may 
arise from any other thought; insomuch that it may 
seem to be a thing indifferent and casual, which thought 
shall follow which. But for the most part this is not 
so uncertain a thing to waking as to sleeping men. For 
the thought or phantasm of the desired end brings 
in all the phantasms, that are means conducing to that 
end, and that in order backwards from the last to the 
first, and again forwards from the beginning to the 
end. But this supposes both appetite, and judgment to 
discern what means conduce to the end, which is gotten 
by experience; and experience is store of phantasms, 
arising from the sense of very many things. For 
<fxLvra£e<rOai and meminisse, fancy and memory, differ 
only in this, that memory supposeth the time past, 
which fancy doth not. In memory, the phantasms we 
consider are as if they were worn out with time; but 
in our fancy we consider them as they are ; which dis- 
tinction is not of the things themselves, but of the con- 
siderations of the sentient. For there is in memory 



124 CONCERNING BODY. 

something like that which happens in looking upon 
things at a great distance ; in which as the small parts 
of the object are not discerned, by reason of their 
remoteness ; so in memory, many accidents and places 
and parts of things, which were formerly perceived by 
sense, are by length of time decayed and lost. 

The perpetual arising of phantasms, both in sense 
and imagination, is that which we commonly call dis- 
course of the mind, and is common to men with other 
living creatures. For he that thinketh, compareth the 
phantasms that pass, that is, taketh notice of their like- 
ness or unlikeness, to one another. And as he that ob- 
serves readily the likenesses of things of different na- 
tures, or that are very remote from one another, is said 
to have a good fancy ; so he is said to have a good judg- 
ment, that finds out the unlikenesses or differences of 
things that are like one another. Now this observation 
of differences is not perception made by a common 
organ of sense, distinct from sense or perception prop- 
erly so called, but is memory of the differences of par- 
ticular phantasms remaining for some time; as the 
distinction between hot and lucid, is nothing else but 
the memory both of a heating, and of an enlightening 
object. 

9. The phantasms of men that sleep, are dreams. 
Concerning which we are taught by experience these 
five things. First, that for the most part there is neither 
order nor coherence in them. Secondly, that we dream 
of nothing but what is compounded and made up of 
the phantasms of sense past. Thirdly, that sometimes 
they proceed, as in those that are drowsy, from the in- 
terruption of their phantasms by little and little, broken 
and altered through sleepiness ; and sometimes also 
they begin in the midst of sleep. Fourthly, that they 



OF SENSE AND ANIMAL MOTION. 125 

are clearer than the imaginations of waking men, ex- 
cept such as are made by sense itself, to which they are 
equal in clearness. Fifthly, that when we dream, we 
admire neither the places nor the looks of the things 
that appear to us. Now from what hath been said, it is 
not hard to show what may be the causes of these phe- 
nomena. For as for the first, seeing all order and co- 
herence proceeds from frequent looking back to the 
end, that is, from consultation; it must needs be, that 
seeing in sleep we lose all thought of the end, our phan- 
tasms succeed one another, not in that order which 
tends to any end, but as it happeneth, and in such man- 
ner, as objects present themselves to our eyes when we 
look indifferently upon all things before us, and see 
them, not because we would see them, but because we 
do not shut our eyes ; for then they appear to us with- 
out any order at all. The second proceeds from this, 
that in the silence of sense there is no new motion from 
the objects, and therefore no new phantasm, un- 
less we call that new, which is compounded of old 
ones, as a chimera, a golden mountain, and the like. 
As for the third, why a dream is sometimes as it were 
the continuation of sense, made up of broken phan- 
tasms, as in men distempered with sickness, the reason 
is manifestly this, that in some of the organs sense 
remains, and in others it faileth. But how some phan- 
tasms may be revived, when all the exterior organs are 
benumbed with sleep, is not so easily shown. Never- 
theless that, which hath already been said, contains the 
reason of this also. For whatsoever strikes the p'ia 
mater, reviveth some of those phantasms that are still in 
motion in the brain ; and when any internal motion of 
the heart reacheth that membrane, then the predomi- 
nant motion in the brain makes the phantasm. Now 



126 CONCERNING BODY. 

the motions of the heart are appetites and aversions, of 
which I shall presently speak further. And as appetites 
and aversions are generated by phantasms, so recip- 
rocally phantasms are generated by appetites and 
aversions. For example, heat in the heart proceeds 
from anger and fighting; and again, from heat in the 
heart, whatsoever be the cause of it, is generated anger 
and the image of an enemy, in sleep. And as love and 
beauty stir up heat in certain organs; so heat in the 
same organs, from whatsoever it proceeds, often 
causeth desire and the image of an unresisting beauty. 
Lastly, cold doth in the same manner generate fear in 
those that sleep, and causeth them to dream of ghosts, 
and to have phantasms of horror and danger; as fear 
also causeth cold in those that wake. So reciprocal are 
the motions of the heart and brain. The fourth, namely, 
that the things we seem to see and feel in sleep, are as 
clear as in sense itself, proceeds from two causes ; one, 
that having then no sense of things without us, that 
internal motion which makes the phantasm, in the ab- 
sence of all other impressions, is predominant ; and the 
other, that the parts of our phantasms which are de- 
cayed and worn out by time, are made up with other 
fictitious parts. To conclude, when we dream, we do 
not wonder at strange places and the appearances of 
things unknown to us, because admiration requires that 
the things appearing be new and unusual, which can 
happen to none but those that remember former appear- 
ances ; whereas in sleep, all things appear as present. 

But it is here to be observed, that certain dreams, 
especially such as some men have when they are be- 
tween sleeping and waking, and such as happen to those 
that have no knowledge of the nature of dreams and 
are withal superstitious, were not heretofore nor are 



OF SENSE AND ANIMAL MOTION. 127 

now accounted dreams. For the apparitions men 
thought they saw, and the voices they thought they 
heard in sleep, were not believed to be phantasms, but 
things subsisting of themselves, and objects without 
those that dreamed. For to some men, as well sleeping 
as waking, but especially to guilty men, and in the 
night, and in hallowed places, fear alone, helped a little 
with the stories of such apparitions, hath raised in their 
minds terrible phantasms, which have been and are still 
deceitfully received for things really true, under the 
names of ghosts and incorporeal substances. 

10. In most living creatures there are observed five 
kinds of senses, which are distinguished by their 
organs, and by their different kinds of phantasms; 
namely, sight, hearing, smell, taste, and touch; and 
these have their organs partly peculiar to each of them 
severally, and partly common to them all. The organ 
of sight is partly animate, and partly inanimate. The 
inanimate parts are the three humours; namely, the 
watery humour, which by the interposition of the mem- 
brane called uvea, the perforation whereof is called the 
apple of the eye, is contained on one side by the first 
concave superficies of the eye, and on the other side by 
the ciliary processes, and the coat of the crystalline 
humor ; the crystalline, which, hanging in the midst be- 
tween the ciliary processes, and being almost of spher- 
ical figure, and of a thick consistence, is enclosed on all 
sides with its own transparent coat ; and the vitreous or 
glassy humour, which filleth all the rest of the cavity of 
the eye, and is somewhat thicker than the watery 
humour, but thinner than the crystalline. The animate 
part of the organ is, first, the membrane choroeides, 
which is a part of the pia mater, saving that it is cov- 
ered with a coat derived from the marrow of the optic 



128 CONCERNING BODY. 

nerve, which is called the retina; and this choroeides, 
seeing it is part of the pia mater, is continued to the 
beginning of the medulla spinalis within the scull, in 
which all the nerves which are within the head have 
their roots. Wherefore all the animal spirits that the 
nerves receive, enter into them there ; for it is not imag- 
inable that they can enter into them anywhere else. 
Seeing therefore sense is nothing else but the action of 
objects propagated to the furthest part of the organ; 
and seeing also that animal spirits are nothing but 
vital spirits purified by the heart, and carried from 
it by the arteries; it follows necessarily, that the ac- 
tion is derived from the heart by some of the arteries 
to the roots of the nerves which are in the head, 
whether those arteries be the plexus retiformis, or 
whether they be other arteries which are inserted 
into the substance of the brain. And, therefore, 
those arteries are the complement or the remaining 
part of the whole organ of sight. And this last part 
is a common organ to all the senses ; whereas, that 
which reacheth from the eye to the roots of the nerves 
is proper only to sight. The proper organ of hearing 
is the tympanum of the ear and its own nerve; from 
which to the heart the organ is common. So the proper 
organs of smell and taste are nervous membranes, in 
the palate and tongue for the taste, and in the nostrils 
for the smell ; and from the roots of those nerves to the 
heart all is common. Lastly, the proper organ of touch 
are nerves and membranes dispersed through the whole 
body; which membranes are derived from the root of 
the nerves. And all things else belonging alike to all 
the senses seem to be administered by the arteries, and 
not by the nerves. 

The proper phantasm of sight is light; and under 



OF SENSE AND ANIMAL MOTION. 129 

this name of light, colour also, which is nothing but 
perturbed light, is comprehended. Wherefore the 
phantasm of a lucid body is light; and of a coloured 
body colour. But the object of sight, properly so called, 
is neither light nor colour, but the body itself which is 
lucid, or enlightened, or coloured. For light and colour, 
being phantasms of the sentient, cannot be accidents of 
the object. Which is manifest enough from this, that 
visible things appear oftentimes in places in which we 
know assuredly they are not, and that in different places 
they are of different colours, and may at one and the 
same time appear in divers places. Motion, rest, mag- 
nitude, and figure, are common both to the sight and 
touch ; and the whole appearance together of figure, and 
light or colour, is by the Greeks commonly called 
clSos, and clSwXov, and tS«x; and by the Latins species 
and imago ; all which names signify no more but 
appearance. 

The phantasm which is made by hearing, is sound; 
by smell, odour ; by taste, savour ; and by touch, hard- 
ness and softness, heat and cold, wetness, oiliness, and 
many more, which are easier to be distinguished by 
sense than words. Smoothness, roughness, rarity, and 
density, refer to figure, and are therefore common both 
to touch and sight. And as for the objects of hearing, 
smell, taste, and touch, they are not sound, odour, 
savour, hardness, &c, but the bodies themselves from 
which sound, odour, savour, hardness, &c. proceed ; of 
the causes of which, and of the manner how they are 
produced, I shall speak hereafter. 

But these phantasms, though they be effects in the 
sentient, as subject, produced by objects working upon 
the organs ; yet there are also other effects besides these, 
produced by the same objects in the same organs; 



130 CONCERNING BODY. 

namely, certain motions proceeding from sense, which 
are called animal motions. For seeing in all sense of 
external things there is mutual action and reaction, that 
is, two endeavours opposing one another, it is manifest 
that the motion of both of them together will be con- 
tinued every way, especially to the confines of both the 
bodies. And when this happens in the internal organ, 
the endeavour outwards will proceed in a solid angle, 
which will be greater, and consequently the idea great- 
er, than it would have been if the impression had been 
weaker. 

ii. From hence the natural cause is manifest, first, 
why those things seem to be greater, which, ceteris 
paribus, are seen in a greater angle : secondly, why in a 
serene cold night, when the moon doth not shine, more 
of the fixed stars appear than at another time. For 
their action is less hindered by the serenity of the air, 
and not obscured by the greater light of the moon, 
which is then absent ; and the cold, making the air more 
pressing, helpeth or strengtheneth the action if the stars 
upon our eyes; in so much as stars may then be seen 
which are seen at no other time. And this may suffice 
to be said in general concerning sense made by the re- 
action of the organ. For, as for the place of the image, 
the deceptions of sight, and other things of which we 
have experience in ourselves by sense, seeing they de- 
pend for the most part upon the fabric itself of the eye 
of man, I shall speak of them then when I come to 
speak of man. 

12. But there is another kind of sense, of which I 
will say something in this place, namely, the sense of 
pleasure and pain, proceeding not from the reaction of 
the heart outwards, but from continual action from the 
outermost part of the organ towards the heart. For 



OF SENSE AND ANIMAL MOTION. 131 

the original of life being in the heart, that motion in 
the sentient, which is propagated to the heart, must 
necessarily make some alteration or diversion of vital 
motion, namely, by quickening or slackening, helping or 
hindering the same. Now when it helpeth, it is pleas- 
ure ; and when it hindereth, it is pain, trouble, grief, &c. 
And as phantasms seem to be without, by reason of the 
endeavour outwards, so pleasure and pain, by reason 
of the endeavour of the organ inwards, seem to be 
within; namely, there where the first cause of the 
pleasure or pain is ; as when the pain proceeds from a 
wound, we think the pain and the wound are both in the 
same place. 

Now vital motion is the motion of the blood, per- 
petually circulating (as hath been shown from many 
infallible signs and marks by Doctor Harvey, the 
first observer of it) in the veins and arteries. Which 
motion, when it is hindered by some other motion made 
by the action of sensible objects, may be restored again 
either by bending or setting strait the parts of the 
body; which is done when the spirits are carried now 
into these, now into other nerves, till the pain, as far as 
is possible, be quite taken away. But if vital motion be 
helped by motion made by sense, then the parts of the 
organ will be disposed to guide the spirits in such 
manner as conduceth most to the preservation and aug- 
mentation of that motion, by the help of the nerves. 
And in animal motion this is the very first endeavour, 
and found even in the embryo ; which while it is in the 
womb, moveth its limbs with voluntary motion, for the 
avoiding of whatsoever troubleth it, or for the pursuing 
of what pleaseth it. And this first endeavour, when it 
tends towards such things as are known by experience 
to be pleasant, is called appetite, that is, an approach- 



132 CONCERNING BODY. 

ing; and when it shuns what is troublesome, aversion, 
or flying from it. And little infants, at the beginning 
and as soon as they are born, have appetite to very few 
things, as also they avoid very few, by reason of their 
want of experience and memory; and therefore they 
have not so great a variety of animal motion as we see 
in those that are more grown. For it is not possible, 
"without such knowledge as is derived from sense, that 
is, without experience and memory, to know what will 
prove pleasant or hurtful ; only there is some place for 
conjecture from the looks or aspects of things. And 
hence it is, that though they do not know what may do 
them good or harm, yet sometimes they approach and 
sometimes retire from the same thing, as their doubt 
prompts them. But afterwards, by accustoming them- 
selves by little and little, they come to know readily 
what is to be pursued and what to be avoided ; and also 
to have a ready use of their nerves and other organs, in 
the pursuing and avoiding of good and bad. Where- 
fore appetite and aversion are the first endeavours of 
animal motion. 

Consequent to this first endeavour, is the impulsion 
into the nerves and retraction again of animal spirits, 
of which it is necessary there be some receptacle or 
place near the original of the nerves ; and this motion 
or endeavour is followed by a swelling and relaxation 
of the muscles ; and lastly, these are followed by con- 
traction and extension of the limbs, which is animal 
motion. 

13. The considerations of appetites and aversions 
are divers. For seeing living creatures have sometimes 
appetite and sometimes aversion to the same thing, as 
they think it will either be for their good or their hurt ; 
while that vicissitude of appetites and aversions remains 



OF SENSE AND ANIMAL MOTION. 133 

in them, they have that series of thoughts which is 
called deliberation; which lasteth as long as they have 
it in their power to obtain that which pleaseth, or to 
avoid that which displeaseth them. Appetite, therefore, 
and aversion are simply so called as long as they follow 
not deliberation. But if deliberation have gone before, 
then the last act of it, if it be appetite, is called will; if 
aversion, unwillingness. So that the same thing is 
called both will and appetite; but the consideration of 
them, namely, before and after deliberation, is divers. 
Nor is that which is done within a man whilst he 
willeth any thing, different from that which is done in 
other living creatures, whilst, deliberation having pre- 
ceded, they have appetite. 

Neither is the freedom of willing or not willing, 
greater in man, than in other living creatures. For 
where there is appetite, the entire cause of appetite hath 
preceded; and, consequently, the act of appetite could 
not choose but follow, that is, hath of necessity fol- 
lowed (as is shown in chapter ix, article 5). And 
therefore such a liberty as is free from necessity, is not 
to be found in the will either of men or beasts. But if 
by liberty we understand the faculty or power, not of 
willing, but of doing what they will, then certainly that 
liberty is to be allowed to both, and both may equally 
have it, whensoever it is to be had. 

Again, when appetite and aversion do with celerity 
succeed one another, the whole series made by them 
hath its name sometimes from one, sometimes from the 
other. For the same deliberation, whilst it inclines 
sometimes to one, sometimes to the other, is from ap- 
petite called hope, and from aversion, fear. For where 
there is no hope, it is not to be called fear, but hate; 
and where no fear, not hope, but desire. To conclude, 



134 CONCERNING BODY. 

all the passions, called passions of the mind, consist of 
appetite and aversion, except pure pleasure and pain, 
which are a certain fruition of good or evil ; as anger 
is aversion from some imminent evil, but such as is 
joined with appetite of avoiding that evil by fprce. But 
because the passions and perturbations of the mind are 
innumerable, and many of them not to be discerned in 
any creatures besides men ; I will speak of them more 
at large in that section which is concerning man. As 
for those objects, if there be any such, which do not at 
all stir the mind, we are said to contemn them. 

And thus much of sense in general. In the next 
place I shall speak of sensible objects. 

CHAPTER XXVI. 

OF THE WORLD AND OF THE STARS. 

I. The magnitude and duration of the world, inscrutable. — 2. 
No place in the world empty. — 3. The arguments of Lucre- 
tius for vacuum, invalid. — 4. Other arguments for the estab- 
lishing of vacuum, invalid. — 5. Six suppositions for the 
solving of the phenomena of nature. — 6. Possible causes of 
the motions annual and diurnal ; and of the apparent direc- 
tion, station, and retrogradation of the planets. — 7. The sup- 
position of simple motion, why likely. — 8. The cause of the 
eccentricity of the annual motion of the earth. — 9. The 
cause why the moon hath always one and the same face 
turned towards the earth. — 10. The cause of the tides of the 
ocean. — 11. The cause of the precession of the equinoxes. 

CHAPTER XXVII. 

OF LIGHT, HEAT, AND OF COLOURS. 

I. Of the immense magnitude of some bodies, and the un- 
speakable littleness of others. — 2. Of the cause of the light of 



OF LIGHT, HEAT, AND OF COLOURS. 135 

the sun. — 3. How light heateth. — 4. The generation of fire 
from the sun. — 5. The generation of fire from collision. 
6. The cause of light in glow-worms, rotten wood, and the 
Bolognan stone. — 7. The cause of light in the concussion of 
sea water. — 8. The cause of flame, sparks, and colliquation. 
9. The cause why wet hay sometimes burns of its own 
accord; also the cause of lightning. — 10. The cause of the 
force of gunpowder ; and what is to be ascribed to the coals, 
what to the brimstone, and what to the nitre. — II. How heat 
is caused by attrition. — 12. The distinction of light into first, 
second, &c. — 13. The causes of the colours we see in looking 
through a prisma of glass, namely, of red, yellow, blue, and 
violet colour. — 14. Why the moon and the stars appear red- 
der in the horizon than in the midst of the heaven. — 15. The 
cause of whiteness. — 16. The cause of blackness. 

I. Besides the stars, of which I have spoken in 
the last chapter, whatsover other bodies there be in the 
world, they may be all comprehended under the name 
of intersidereal bodies. And these I have already sup- 
posed to be either the most fluid aether, or such bodies 
whose parts have some degree of cohesion. Now, 
these differ from one another in their several consisten- 
cies, magnitudes, motions, and figures. In consistency, 
I suppose some bodies to be harder, others softer 
through all the several degrees of tenacity. In magni- 
tude, some to be greater, others less, and many un- 
speakably little. For we must remember that, by the 
understanding, quantity is divisible into divisibles per- 
petually. And therefore, if a man could do as much 
with his hands as he can with his understanding, he 
would be able to take from any given magnitude a part 
which should be less than any other magnitude given. 
But the Omnipotent Creator of the world can actually 
from a part of any thing take another part, as far as 
we by our understanding can conceive the same to be 



136 CONCERNING BODY. 

divisible. Wherefore there is no impossible smallness 
of bodies. And what hinders but that we may think 
this likely? For we know there are some living crea- 
tures so small that we can scarce see their whole bodies. 
Yet even these have their young ones ; their little veins 
and other vessels, and their eyes so small as that no 
microscope can make them visible. So that we cannot 
suppose any magnitude so little, but that our very sup- 
position is actually exceeded by nature. Besides, there 
are now such microscopes commonly made, that the 
things we see with them appear a hundred thousand 
times bigger than they would do if we looked upon 
them with our bare eyes. Nor is there any doubt but 
that by augmenting the power of these microscopes 
(for it may be augmented as long as neither matter 
nor the hands of workmen are wanting) every one of 
those hundred thousandth parts might yet appear a 
hundred thousand times greater than they did before. 
Neither is the smallness of some bodies to be more ad- 
mired than the vast greatness of others. For it belongs 
to the same Infinite Power, as well to augment infinitely 
as infinitely to diminish. To make the great orb, 
namely, that whose radius reacheth from the earth to 
the sun, but as a point in respect of the distance be- 
tween the sun and the fixed stars ; and, on the contrary, 
to make a body so little, as to be in the same proportion 
less than any other visible body, proceeds equally from 
one and the same Author of Nature. But this of the 
immense distance of the fixed stars, which for a long 
time was accounted an incredible thing, is now believed 
by almost all the learned. Why then should not that 
other, of the smallness of some bodies, become credible 
at some time or other? For the Majesty of God ap- 
pears no less in small things than in great; and as it 



OF LIGHT, HEAT, AND OF COLOURS. 137 

exceedeth human sense in the immense greatness of the 
universe, so also it doth in the smallness of the parts 
thereof. Nor are the first elements of compositions, 
nor the first beginnings of actions, nor the first mo- 
ments of times more credible, than that which is now 
believed of the vast distance of the fixed stars. 

Some things are acknowledged by mortal men to 
be very great, though finite, as seeing them to be such. 
They acknowledge also that some things, which they 
do not see, may be of infinite magnitude. But they 
are not presently nor without great study persuaded, 
that there is any mean between infinite and the great- 
est of those things which either they see or imagine. 
Nevertheless, when after meditation and contempla- 
tion many things which we wondered at before are 
now grown more familiar to us, we then believe them, 
and transfer our admiration from the creatures to the 
Creator. But how little soever some bodies may be, 
yet I will not suppose their quantity to be less than is 
requisite for the solving of the phenomena. And in 
like manner I shall suppose their motion, namely, their 
velocity and slowness, and the variety of their figures, 
to be only such as the explication of their natural 
causes requires. And lastly, I suppose, that the parts 
of the pure aether, as if it were the first matter, have 
no motion at all but what they receive from bodies 
which float in them, and are not themselves fluid. 

2. Having laid these grounds, let us come to speak 
of causes; and in the first place let us inquire what 
may be the cause of the light of the sun. Seeing, 
therefore, the body of the sun doth by its simple circu- 
lar motion thrust away the ambient ethereal substance 
sometimes one way sometimes another, so that those 
parts, which are next the sun, being moved by it, do 



138 CONCERNING BODY. 

propagate that motion to the next remote parts, and 
these to the next, and so on continually ; it must needs 
be that, notwithstanding any distance, the foremost 
part of the eye will at last be pressed ; and by the pres- 
sure of that part, the motion will be propagated to the 
innermost part of the organ of sight, namely, to the 
heart; and from the reaction of the heart, there will 
proceed an endeavour back by the same way, ending 
in the endeavour outwards of the coat of the eye, 
called the retina. But this endeavour outwards, as 
has been defined in chapter xxv, is the thing which is 
called light, or the phantasm of a lucid body. For it 
is by reason of this phantasm that an object is called 
lucid. Wherefore we have a possible cause of the 
light of the sun ; which I undertook to find. 

3. The generation of the light of the sun is accom- 
panied with the generation of heat. Now every man 
knows what heat is in himself, by feeling it when he 
grows hot; but what it is in other things, he knows 
only by ratiocination. For it is one thing to grow 
hot, and another thing to heat or make hot. And 
therefore though we perceive that the fire or the sun 
heateth, yet we do not perceive that it is itself hot. 
That other living creatures, whilst they make other 
things hot, are hot themselves, we infer by reasoning 
from the like sense in ourselves. But this is not a 
necessary inference. For though it may truly be 
said of living creatures, that they heat, therefore they 
are themselves hot; yet it cannot from hence be truly 
inferred that fire heateth, therefore it is itself hot; no 
more than this, fire cause th pain, therefore it is itself 
in pain. Wherefore, that is only and properly called 
hot, which when we feel we are necessarily hot. 

Now when we grow hot, we find that our spirits 



OF LIGHT, HEAT, AND OF COLOURS. 139 

and blood, and whatsoever is fluid within us, is called 
out from the internal to the external parts of our bod- 
ies, more or less, according to the degree of the heat; 
and that our skin swelleth. He, therefore, that can 
give a possible cause of this evocation and swelling, 
and such as agrees with the rest of the phenomena of 
heat, may be thought to have given the cause of the 
heat of the sun. 

It hath been shown, in the 5th article of chapter 
xxi, that the fluid medium, which we call the air, is so 
moved by the simple circular motion of the sun, as 
that all its parts, even the least, do perpetually change 
places with one another; which change of places is 
that which there I called fermentation. From this 
fermentation of the air, I have, in the 8th article of the 
last chapter, demonstrated that the water may be 
drawn up into the clouds. 

And I shall now show that the fluid parts may, in 
like manner, by the same fermentation, be drawn out 
from the internal to the external parts of our bodies. 
For seeing that wheresoever the fluid medium is con- 
tiguous to the body of any living creature, there the 
parts of that medium are, by perpetual change of 
place, separated from one another; the contiguous 
parts of the living creature must, of necessity, en- 
deavour to enter into the spaces of the separated parts. 
For otherwise those parts, supposing there is no vacu- 
um, would have no place to go into. And therefore 
that, which is most fluid and separable in the parts of 
the living creature which are contiguous to the me- 
dium, will go first out ; and into the place thereof will 
succeed such other parts as can most easily transpire 
through the pores of the skin. And from hence it is 
necessary that the rest of the parts, which are not sep- 



140 CONCERNING BODY. 

arated, must altogether be moved outwards, for the 
keeping of all places full. But this motion outwards 
of all parts together must, of necessity, press those 
parts of the ambient air which are ready to leave their 
places, and therefore all the parts of the body, en- 
deavouring at once that way, make the body swell. 
Wherefore a possible cause is given of heat from the 

sun ; which was to be done. 

********* 

CHAPTER XXVIII. 

OF COLD, WIND, HARD, ICE, RESTITUTION OF BODIES 
BENT, DIAPHONOUS, LIGHTNING AND THUNDER J AND 
OF THE HEADS OF RIVERS. 

I. Why breath from the same mouth sometimes heats and 
sometimes cools. — 2. Wind, and the inconstancy of winds, 
whence. — 3. Why there is a constant, though not a great 
wind, from east to west, near the equator. — 4. What is the 
effect of air pent in between the clouds. — 5. No change from 
soft to hard, but by motion. — 6. What is the cause of cold 
near the poles. — 7. The cause of ice; and why the cold is 
more remiss in rainy than in clear weather. Why water 
doth not freeze in deep wells as it doth near the superficies 
of the earth. Why ice is not so heavy as water; and why 
wine is not so easily frozen as water. — 8. Another cause of 
hardness from the fuller contact of atoms; also, how hard 
things are broken. — 9. A third cause of hardness from heat. 
10. A fourth cause of hardness from the motion of atoms 
enclosed in a narrow space. — II. How hard things are soft- 
ened. — 12. Whence proceed the spontaneous restitution of 
things bent. — 13. Diaphanous and opacous, what they are, 
and whence. — 14. The cause of lightning and thunder — 15. 
Whence it proceeds that clouds can fall again after they are 
once elevated and frozen. — 16. How it could be that the 
moon was eclipsed, when she was not diametrically opposite 



OF SOUND, ODOUR, SAVOUR, AND TOUCH. 141 

to the sun. — 17. By what means many sums may appear at 
once. — 18. Of the heads of rivers. 

CHAPTER XXIX. 

OF SOUND, ODOUR, SAVOUR, AND TOUCH. 

I. The definition of sound, and the distinctions of sounds. 
2. The cause of the degrees of sounds. — 3. The difference 
between sounds acute and grave. — 4. The difference between 
clear and hoarse sounds, whence.— 5. The sound of thunder 
and of a gun, whence it proceeds. — 6. Whence it is that 
pipes, by blowing into them, have a clear sound. — 7. Of re- 
flected sound. — 8. From whence it is that sound is uniform 
and lasting. — 9. How sound may be helped and hindered by 
the wind. — 10. Not only air, but other bodies how hard so- 
ever they be, convey sound. — n. The causes of grave and 
acute sounds, and of concent. — 12. Phenomena for smelling. 
— 13. The first organ and the generation of smelling. — 14. 
How it is helped by heat and by wind. — 15. Why such bodies 
are least smelt, which have least intermixture of air in them. 
— 16. Why odorous things become more odorous by being 
bruised. — 17. The first organ of tasting; and why some 
savours cause nauseousness. — 18. The first organ of feeling; 
and how we come to the knowledge of such objects as are 
common to the touch and other senses. 

I. Sound is sense generated by the action of the 
medium, when its motion reacheth the ear and the rest 
of the organs of sense. Now, the motion of the me- 
dium is not the sound itself, but the cause of it. For 
the phantasm which is made in us, that is to say, the 
reaction of the organ, is properly that which we call 
sound. 

The principal distinctions of sounds are these; first, 
that one sound is stronger, another weaker. Second- 
ly, that one is more grave, another more acute. 
Thirdly, that one is clear, another hoarse. Fourthly, 



142 • CONCERNING BODY. 

that one is primary, another derivative. Fifthly, that 
one is uniform, another not. Sixthly, that one is more 
durable, another less durable. Of all which distinc- 
tions the members may be sub-distinguished into parts 
distinguishable almost infinitely. For the variety of 
sounds seems to be not much less than that of colours. 

As vision, so hearing is generated by the motion of 
the medium, but not in the same manner. For sight is 
from pressure, that is, from an endeavour; in which 
there is no perceptible progression of any of the parts 
of the medium; but one part urging or thrusting on 
another propagateth that action successively to any 
distance whatsoever; whereas the motion of the me- 
dium, by which sound is made, is a stroke. For when 
we hear, the drum of the ear, which is the first organ 
of hearing, is stricken; and the drum being stricken, 
the pia mater is also shaken, and with it the arteries 
which are inserted into it; by which the action being 
propagated to the heart itself, by the reaction of the 
heart a phantasm is made which we call sound; and 
because the reaction tendeth outwards, we think it is 
without. 

2. And seeing the effects produced by motion are 
greater or less, not only when the velocity is greater 
or less, but also when the body hath greater or less 
magnitude though the velocity be the same; a sound 
may be greater or less both these ways. And because 
neither the greatest nor the least magnitude or ve- 
locity can be given, it may happen that either the mo- 
tion may be of so small velocity, or the body itself of 
so small magnitude, as to produce no sound at all ; or 
either of them may be so great, as to take away the 
faculty of sense by hurting the organ. 

From hence may be deduced possible causes of the 



OF SOUND, ODOUR, SAVOUR, AND TOUCH. 143 

strength and weakness of sounds in the following 
phenomena. 

The first whereof is this, that if a man speak 
through a trunk which hath one end applied to the 
mouth of the speaker, and the other to the ear of the 
hearer, the sound will come stronger than it would 
do through the open air. And the cause, not only the 
possible, but the certain and manifest cause is this, 
that the air which is moved by the first breath and 
carried forwards in the trunk, is not diffused as it 
would be in the open air, and is consequently brought 
to the ear almost with the same velocity with which 
it was first breathed out. Whereas, in the open air, 
the first motion diffuseth itself every way into circles, 
such as are made by the throwing of a stone into a 
standing water, where the velocity grows less and less 
as the undulation proceeds further and further from 
the beginning of its motion. 

The second is this, that if the trunk be short, and 
the end which is applied to the mouth be wider than 
that which is applied to the ear, thus also the sound 
will be stronger than if it were made in the open air. 
And the cause is the same, namely, that by how much 
the wider end of the trunk is less distant from the 
beginning of the sound, by so much the less is the 
diffusion. 

The third, that it is easier for one, that is within a 
chamber, to hear what is spoken without, than for 
him, that stands without, to hear what is spoken with- 
in. For the windows and other inlets of the moved 
air are as the wide end of the trunk. And for this 
reason some creatures seem to hear the better, because 
nature has bestowed upon them wide and capacious 
ears. 



144 CONCERNING BODY. 

The fourth is this, that though he, which standeth 
upon the sea-shore, cannot hear the collision of the 
two nearest waves, yet nevertheless he hears the roar- 
ing of the whole sea. And the cause seems to be this, 
that though the several collisions move the organ, yet 
they are not severally great enough to cause sense; 
whereas nothing hinders but that all of them together 
may make sound. 

3. That bodies when they are stricken do yield 
some a more grave, others a more acute sound, the 
cause may consist in the difference of the times in 
which the parts stricken and forced out of their places 
return to the same places again. For in some bodies, 
the restitution of the moved parts is quick, in others 
slow. And this also may be the cause, why the parts 
of the organ, which are moved by the medium, return 
to their rest again, sometimes sooner, sometimes later. 
Now, by how much the vibrations or the reciprocal 
motions of the parts are more frequent, by so much 
doth the whole sound made at the same time by one 
stroke consist of more, and consequently of smaller 
parts. For what is acute in sound, the same is subtle 
in matter ; and both of them, namely acute sound and 
subtle matter, consist of very small parts, that of time, 
and this of the matter itself. 

The third distinction of sounds cannot be conceived 
clearly enough by the names I have used of clear and 
hoarse, nor by any other that I know; and therefore 
it is needful to explain them by examples. When I 
say hoarse, I understand whispering and hissing, and 
whatsoever is like to these, by what appellation soever 
it be expressed. And sounds of this kind seem to be 
made by the force of some strong wind, raking rather 
than striking such hard bodies as it falls upon. On 



OF SOUND, ODOUR, SAVOUR, AND TOUCH. 145 

the contrary, when I use the word clear, I do not un- 
derstand such a sound as may be easily and distinctly 
heard; for so whispers would be clear; but such as is 
made by somewhat that is broken, and such as is 
clamour, tinkling, the sound of a trumpet, &c, and to 
express it significantly in one word, noise. And see- 
ing no sound is made but by the concourse of two 
bodies at the least, by which concourse it is necessary 
that there be as well reaction as action, that is to say, 
one motion opposite to another ; it follows that accord- 
ing as the proportion between those two opposite mo- 
tions is diversified, so the sounds which are made 
will be different from one another. And whensoever 
the proportion between them is so great, as that the 
motion of one of the bodies be insensible if compared 
with the motion of the other, then the sound will not 
be of the same kind ; as when the wind falls very ob- 
liquely upon a hard body, or when a hard body is car- 
ried swiftly through the air; for then there is made 
that sound which I call a hoarse sound, in Greek 
crvpiy/Kos. Therefore the breath blown with violence 
from the mouth makes a hissing, because in going out 
it rakes the superficies of the lips, whose reaction 
against the force of the breath is not sensible. And 
this is the cause why the winds have that hoarse sound. 
Also if two bodies, how hard soever, be rubbed to- 
gether with no great pressure, they make a hoarse 
sound. And this hoarse sound, when it is made, as 
I have said, by the air raking the superficies of a hard 
body, seemeth to be nothing but the dividing of the 
air into innumerable and very small files. For the 
asperity of the superficies doth, by the eminences of 
its innumerable parts, divide or cut in pieces the air 
that slides upon it. 



146 CONCERNING BODY. 

4. Noise, or that which I call clear sound, is made 
two ways; one, by two hoarse sounds made by oppo- 
site motions ; the other, by collision, or by the sudden 
pulling asunder of two bodies, whereby their small 
particles are put into commotion, or being already in 
commotion suddenly restore themselves again; which 
motion, making impression upon the medium, is prop- 
agated to the organ of hearing. And seeing there is 
in this collision or divulsion an endeavour in the par- 
ticles of one body, opposite to the endeavour of the 
particles of the other body, there will also be made in 
the organ of hearing a like opposition of endeavours, 
that is to say, of motions ; and consequently the sound 
arising from thence will be made by two opposite 
motions, that is to say, by two opposite hoarse sounds 
in one and the same part of the organ. For, as I 
have already said, a hoarse sound supposeth the sensi- 
ble motion of but one of the bodies. And this oppo- 
sition of motions in the organ is the cause why two 
bodies make a noise, when they are either suddenly 
stricken against one another, or suddenly broken 
asunder. 

12. For the finding out the cause of smells, I shall 
make use of the evidence of these following phenom- 
ena. First, that smelling is hindered by cold, and 
helped by heat. Secondly, that when the wind blow- 
eth from the object, the smell is the stronger; and, 
contrarily, when it bloweth from the sentient towards 
the object, the weaker; both which phenomena are, 
by experience, manifestly found to be true in dogs, 
which follow the track of beasts by the scent. Third- 
ly, that such bodies, as are less pervious to the fluid 
medium, yield less smell than such as are more per- 



OF SOUND, ODOUR, SAVOUR, AND TOUCH. 147 

vious; as may be seen in stones and metals, which, 
compared with plants and living creatures, and their 
parts, fruits and excretions, have very little or no 
smell at all. Fourthly, that such bodies, as are of 
their own nature odorous, become yet more odorous 
when they are bruised. Fifthly, that when the breath 
is stopped, at least in men, nothing can be smelt. 
Sixthly, that the sense of smelling is also taken away 
by the stopping of the nostrils, though the mouth be 
left open. 

13. By the fifth and sixth phenomenon it is mani- 
fest, that the first and immediate organ of smelling 
is the innermost cuticle of the nostrils, and that part 
of it, which is below the passage common to the nos- 
trils and the palate. For when we draw breath by 
the nostrils we draw it into the lungs. That breath, 
therefore, which conveys smells is in the way which 
passeth to the lungs, that is to say, in that part of the 
nostrils which is below the passage through which 
the breath goeth. For, nothing is smelt, neither be- 
yond the passage of the breath within, nor at all with- 
out the nostrils. 

And seeing that from different smells there must 
necessarily proceed some mutation in the organ, and 
all mutation is motion ; it is therefore also necessary 
that, in smelling, the parts of the organ, that is to say of 
that internal cuticle and the nerves that are inserted in- 
to it, must be diversely moved by different smells. And 
seeing also, that it hath been demonstrated, that noth- 
ing can be moved but by a body that is already moved 
and contiguous; and that there is no other body con- 
tiguous to the internal membrane of the nostrils but 
breath, that is to say attracted air, and such little solid 
invisible bodies, if there be any such, as are intermin- 



I4& CONCERNING BODY. 

gled with the air ; it follows necessarily, that the cause 
of smelling is either the motion of that pure air or 
ethereal substance, or the motion of those small bod- 
ies. But this motion is an effect proceeding from the 
object of smell, and therefore, either the whole object 
itself or its several parts must necessarily be moved. 
Now, we know that odorous bodies make odour, 
though their whole bulk be not moved. Wherefore 
the cause of odour is the motion of the invisible parts 
of the odorous body. And these invisible parts do 
either go out of the object, or else, retaining their 
former situation with the rest of the parts, are moved 
together with them, that is to say, they have simple 
and invisible motion. They that say, there goes 
something out of the odorous body, call it an efflu- 
vium; which effluvium is either of the ethereal sub- 
stance, or of the small bodies that are intermingled 
with it. But, that all variety of odours should pro- 
ceed from the effluvia of those small bodies that are 
intermingled with the ethereal substance, is altogether 
incredible, for these considerations; first, that certain 
unguents, though very little in quantity, do neverthe- 
less send forth very strong odours, not only to a great 
distance of place, but also for a great continuance of 
time, and are to be smelt in every point both of that 
place and time; so that the parts issued out are suffi- 
cient to fill ten thousand times more space, than the 
whole odorous body is able to fill; which is impossi- 
ble. Secondly, that whether that issuing out be with 
strait or with crooked motion, if the same quantity 
should flow from any other odorous body with the 
same motion, it would follow that all odorous bodies 
would yield the same smell. Thirdly, that seeing 
those effluvia have great velocity of motion (as is 



OF SOUND, ODOUR, SAVOUR, AND TOUCH. 149 

manifest from this, that noisome odours proceeding 
from caverns are presently smelt at a great distance) 
it would follow, that, by reason there is nothing to 
hinder the passage of those effluvia to the organ, such 
motion alone were sufficient to cause smelling; which 
is not so; for we cannot smell at all, unless we draw 
in our breath through our nostrils. Smelling, there- 
fore, is not caused by the effluvium of atoms ; nor, for 
the same reason, is it caused by the effluvium of 
ethereal substance; for so also we should smell with- 
out the drawing in of our breath. Besides, the ethe- 
real substance being the same in all odorous bodies, 
they would always affect the organ in the same man- 
ner ; and, consequently, the odours of all things would 
be alike. 

It remains, therefore, that the cause of smelling 
must consist in the simple motion of the parts of 
odorous bodies without any efflux or diminution of 
their whole substance. And by this motion there is 
propagated to the organ, by the intermediate air, the 
like motion, but not strong enough to excite sense of 
itself without the attraction of air by respiration. 
And this is a possible cause of smelling. 

14. The cause why smelling is hindered by cold 
and helped by heat may be this; that heat, as hath 
been shown in chapter xxi, generateth simple motion ; 
and therefore also, wheresoever it is already, there it 
will increase it; and the cause of smelling being in- 
creased, the smell itself will also be increased. As 
for the cause why the wind blowing from the object 
makes the smell the stronger, it is all one with that 
for which the attraction of air in respiration doth the 
same. For, he that draws in the air next to him, 
draws with it by succession that air in which is the 



ISO CONCERNING BODY. 

object. Now, this motion of the air is wind, and, 
when another wind bloweth from the object, will be 
increased by it. 

15. That bodies which contain the least quantity 
of air, as stones and metals, yield less smell than 
plants and living creatures; the cause may be, that 
the motion, which causeth smelling, is a motion of the 
fluid parts only ; which parts, if they have any motion 
from the hard parts in which they are contained, they 
communicate the same to the open air, by which it is 
propagated to the organ. Where, therefore, there 
are no fluid parts as in metals, or where the fluid parts 
receive no motion from the hard parts, as in stones, 
which are made hard by accretion, there can be no 
smell. And therefore also the water, whose parts 
have little or no motion, yieldeth no smell. But, if 
the same water, by seeds and the heat of the sun, be 
together with particles of earth raised into a plant, 
and be afterwards pressed out again, it will be odorous, 
as wine from the vine. And as water passing 
through plants is by the motion of the parts of those 
plants made an odorous liquor, so also of air, passing 
through the same plants whilst they are growing, are 
made odorous airs. And thus also it is with the 
juices and spirits, which are bred in living creatures. 

16. That odorous bodies may be made more odor- 
ous by contrition proceeds from this, that being brok- 
en into many parts, which are all odorous, the air, 
which by respiration is drawn from the object towards 
the organ, doth in its passage touch upon all those 
parts, and receive their motion. Now, the air touch- 
eth the superficies only ; and a body having less super- 
ficies whilst it is whole, than all its parts together 
have after it is reduced to powder, it follows that the 



OF SOUND, ODOUR, SAVOUR, AND TOUCH. 151 

same odorous body yieldeth less smell whilst it is 
whole, than it will do after it is broken into smaller 
parts. And thus much of smells. 

17. The taste follows; whose generation hath this 
difference from that of the sight, hearing, and smell- 
ing, that by these we have sense of remote objects; 
whereas, we taste nothing but what is contiguous, and 
doth immediately touch either the tongue or palate, or 
both. From whence it is evident, that the cuticles of 
the tongue and palate, and the nerves inserted into 
them are the first organ of taste; and (because from 
the concussion of the parts of these, there followeth 
necessarily a concussion of the pia mater) that the 
action communicated to these is propagated to the 
brain, and from thence to the farthest organ, namely, 
the heart, in whose reaction consisteth the nature of 
sense. 

Now, that savours, as well as odours, do not only 
move the brain but the stomach also, as is manifest 
by the loathings that are caused by them both; they, 
that consider the organ of both these senses, will not 
wonder at all; seeing the tongue, the palate and the 
nostrils, have one and the same continued cuticle, de- 
rived from the dura mater. 

And that effluvia have nothing to do in the sense of 
tasting, is manifest from this, that there is no taste 
where the organ and the object are not contiguous. 

By what variety of motions the different kinds of 
tastes, which are innumerable, may be distinguished, 
I know not. I might with others derive them from 
the divers figures of those atoms, of which whatsoever 
may be tasted consisteth ; or from the diverse motions 
which I might, by way of supposition, attribute to 
those atoms; conjecturing, not without some likeli- 



152 CONCERNING BODY. 

hood of truth, that such things as taste sweet have 
their particles moved with slow circular motion, and 
their figures spherical ; which makes them smooth and 
pleasing to the organ ; that bitter things have circular 
motion, but vehement, and their figures full of an- 
gles, by which they trouble the organ; and that sour 
things have strait and reciprocal motion, and their 
figures long and small, so that they cut and wound 
the organ. And in like manner I might assign for 
the causes of other tastes such several motions and 
figures of atoms, as might in probability seem to be 
the true causes. But this would be to revolt from 
philosophy to divination. 

1 8. By the touth we feel what bodies are cold or 
hot, though they be distant from us. Others, as hard, 
soft, rough, and smooth, we cannot feel unless they 
be contiguous. The organ of touch is every one of 
those membranes, which being continued from the 
pia mater are so diffused throughout the whole body, 
as that no part of it can be pressed, but the pia mater 
is pressed together with it. Whatsoever therefore 
presseth it, is felt as hard or soft, that is to say, as 
more or less hard. And as for the sense of rough, it 
is nothing else but innumerable perceptions of hard 
and hard succeeding one another by short intervals 
both of time and place. For we take notice of rough 
and smooth, as also of magnitude and figure, not 
only by the touch, but also by memory. For though 
some things are touched in one point, yet rough and 
smooth, like quantity and figure, are not perceived 
but by the flux of a point, that is to say, we have no 
sense of them without time ; and we can have no sense 

of time without memory. 

********* 



OF GRAVITY. 153 

CHAPTER XXX. 

OF GRAVITY. 

I. A thick body doth not contain more matter, unless also 
more place, than a thin. — 2. That the descent of heavy bod- 
ies proceeds not from their own appetite, but from some 
power of the earth. — 3. The difference of gravities proceed- 
eth from the difference of the impetus with which the ele- 
ments, whereof heavy bodies are made, do fall upon the 
earth. — 4. The cause of the descent of heavy bodies. — 5. In 
what proportion the descent of heavy bodies is accelerated. — 
6. Why those that dive do not, when they are under water, 
feel the weight of the water above them. — 7. The weight of 
a body that floateth, is equal to the weight of so much 
water as would fill the space, which the immersed part of the 
body takes up within the water. — 8. If a body be lighter 
than water, then how big soever that body be, it may float 
upon any quantity of water, how little soever. — 9. How 
water may be lifted up and forced out of a vessel by air. — 
10. Why a bladder is heavier when blown full of air, than 
when it is empty. — II. The cause of the ejection upwards 
of heavy bodies from a wind-gun. — 12. The cause of the 
ascent of water in a weather-glass. — 13. The cause of mo- 
tion upwards in living creatures. — 14. That there is in nature 
a kind of body heavier than air, which nevertheless is not by 
sense distinguishable from it. — 15. Of the cause of magnet- 
ical virtue. 
********* 

15. And thus much concerning the nature of body 
in general; with which I conclude this my first sec- 
tion of the Elements of Philosophy. In the first, sec- 
ond, and third parts, where the principles of ratio- 
cination consist in our own understanding, that is to 
say, in the legitimate use of such words as we our- 
selves constitute, all the theorems, if I be not de- 
ceived, are rightly demonstrated. The fourth part 



154 CONCERNING BODY. 

depends upon hypotheses; which unless we know 
them to be true, it is impossible for us to demonstrate 
that those causes, which I have there explicated, are 
the true causes of the things whose productions I have 
derived from them. 

Nevertheless, seeing I have assumed no hypothesis, 
which is not both possible and easy to be compre- 
hended; and seeing also that I have reasoned aright 
from those assumptions, I have withal sufficiently 
demonstrated that they may be the true causes ; which 
is the end of physical contemplation. If any other 
man from other hypotheses shall demonstrate the 
same or greater things, there will be greater praise 
and thanks due to him than I demand for myself, pro- 
vided his hypotheses be such as are conceivable. For 
as for those that say anything may be moved or pro- 
duced by itself, by species, by its own power, by 
substantial forms, by incorporeal substances, by in- 
stinct, by antiperistasis, by antipathy, sympathy, oc- 
cult quality, and other empty words of schoolmen, 
their saying so is to no purpose. 

And now I proceed to the phenomena of man's 
body; where I shall speak of the optics, and of the 
dispositions, affections, and manners of men, if it shall 
please God to give me life, and show their causes. 



THE DOCTRINE OF HOBBES CONCERNING 
THE UNREALITY OF CON- 
SCIOUSNESS. 



HUMAN NATURE. 
CHAPTER II. 



HUMAN NATURE. 

CHAPTER II. 

2. Definition of sense. 4. Four propositions concerning the 
nature of conceptions. 5. The first proved. 6. The second 
proved. 7, 8. The third proved. 9. The fourth proved. 
10. The main deception of sense. 

i. Having declared what I mean by the word 
conception, and other words equivalent thereunto, I 
come to the conceptions themselves, to shew their dif- 
ferences, their causes, and the manner of the produc- 
tion, so far as is necessary for this place. 

2. Originally all conceptions proceed from the ac- 
tion of the thing itself, whereof it is the conception: 
now when the action is present, the conception it pro- 
duceth is also called sense; and the thing by whose 
action the same is produced, is called the object of 
the sense. 

3. By our several organs we have several concep- 
tions of several qualities in the objects; for by sight 
we have a conception or image composed of colour 
and figure, which is all the notice and knowledge the 
object imparteth to us of its nature by the eye. By 
hearing we have a conception called sound, which is 
all the knowledge we have of the quality of the object 
from the ear. And so the rest of the senses are also 
conceptions of several qualities, or natures of their 
objects. 

4. Because the image in vision consisting of colour 
and shape is the knowledge we have of the qualities 
of the object of that sense; it is no hard matter for 

i57 



158 HUMAN NATURE. 

a man to fall into this opinion, that the same colour 
and shape are the very qualities themselves ; and for 
the same cause, that sound and noise are the qualities 
of the bell, or of the air. And this opinion hath been 
so long received, that the contrary must needs appear 
a great paradox; and yet the introduction of species 
visible and intelligible (which is necessary for the 
maintenance of that opinion) passing to and fro from 
the object, is worse than any paradox, as being a plain 
impossibility. I shall therefore endeavour to make 
plain these points : 

That the subject wherein colour and image are in- 
herent, is not the object or thing seen. 

That there is nothing without us (really) which we 
call an image or colour. 

That the said image or colour is but an apparition 
unto us of the motion, agitation, or alteration, which 
the object worketh in the brain, or spirit, or some in- 
ternal substance of the head. 

That as in vision, so also in conceptions that arise 
from the other senses, the subject of their inherence is 
not the object, but the sentient. 

5. Every man hath so much experience as to have 
seen the sun and the other visible objects by reflection 
in the water and glasses; and this alone is sufficient for 
this conclusion, that colour and image may be there 
where the thing seen is not. But because it may be 
said that notwithstanding the image in the water be 
not in the object, but a thing merely phantastical, 
yet there may be colour really in the thing itself: I 
will urge further this experience, that divers times men 
see directly the same object double, as two candles for 
one, which may happen from distemper, or otherwise 
without distemper if a man will, the organs being 



HUMAN NATURE. 159 

either in their right temper, or equally distempered; 
the colours and figures in two such images of the 
same thing cannot be inherent therein, because the 
thing seen cannot be in two places. 

One of these images therefore is not inherent in the 
object: but seeing the organs of the sight are then in 
equal temper or distemper, the one of them is no more 
inherent than the other; and consequently neither of 
them both are in the object; which is the first proposi- 
tion, mentioned in the precedent number. 

6. Secondly, that the image of any thing by re- 
flection in a glass or water or the like, is not any thing 
in or behind the glass, or in or under the water, every 
man may grant to himself ; which is the second propo- 
sition. 

7. For the third, we are to consider, first that upon 
every great agitation or concussion of the brain (as it 
happeneth from a stroke, especially if the stroke be 
upon the eye) whereby the optic nerve suffereth any 
great violence, there appeareth before the eyes a cer- 
tain light, which light is nothing without, but an ap- 
parition only, all that is real being the concussion or 
motion of the parts of that nerve; from which ex- 
perience we may conclude, that apparition of light is 
really nothing but motion within. If therefore from 
lucid bodies there can be derived motion, so as to affect 
the optic nerve in such manner as is proper thereunto, 
there will follow an image of light somewhere in that 
line by which the motion was last derived to the eye; 
that is to say, in the object, if we look directly on it, 
and in the glass or water, when we look upon it in 
the line of reflection, which in effect is the third propo- 
sition ; namely, that image and colour is but an appari- 
tion to us of that motion, agitation, or alteration which 



160 HUMAN NATURE. 

the object worketh in the brain or spirits, or some 
internal substance in the head. 

8. But that from all lucid, shining and illuminate 
bodies, there is a motion produced to the eye, and, 
through the eye, to the dptic nerve, and so into the 
brain, by which that apparition of light or colour is 
affected, is not hard to prove. And first, it is evident 
that the fire, the only lucid body here upon earth, 
worketh by motion equally every way; insomuch as 
the motion thereof stopped or inclosed, it is presently 
extinguished, and no more fire. And further, that that 
motion, whereby the fire worketh, is dilation, and con- 
traction of itself alternately, commonly called scintilla- 
tion or glowing, is manifest also by experience. 
From such motion in the fire must needs arise a rejec- 
tion or casting from itself of that part of the medium 
which is contiguous to it, whereby that part also re- 
jecteth the next, and so successively one part beateth 
back another to the very eye; and in the same manner 
the exterior part of the eye presseth the interior, (the 
laws of refraction still observed). Now the interior 
coat of the eye is nothing else but a piece of the optic 
nerve; and therefore the motion is still continued 
thereby into the brain, and by resistance or reaction of 
the brain, is also a rebound into the optic nerve again ; 
which we not conceiving as motion or rebound from 
within, do think it is without, and call it light ; as hath 
been already shewed by the experience of a stroke. 
We have no reason to doubt, that the fountain of 
light, the sun, worketh by any other ways than the fire, 
at least in this matter. And thus all vision hath its 
original from such motion as is here described: for 
where there is no light, there is no sight; and therefore 
colour also must be the same thing with light, as being 



HUMAN NATURE. 161 

the effect of the lucid bodies: their difference being 
only this, that when the light cometh directly from the 
fountain to the eye, or indirectly by reflection from 
clean and polite bodies, and such as have not any par- 
ticular motion internal to alter it, we call it light; 
but when it cometh to the eye by reflection from 
uneven, rough, and coarse bodies, or such as are 
affected with internal motion of their own that may 
alter it, then we call it colour; colour and light differ- 
ing only in this, that the one is fyure, and the other 
perturbed light. By that which hath been said, not 
only the truth of the third proposition, but also the 
whole manner of producing light and colour, is ap- 
parent. 

9. As colour is not inherent in the object, but an 
effect thereof upon us, caused by such motion in the 
object, as hath been described: so neither is sound 
in the thing we hear, but in ourselves. One manifest 
sign thereof is, that as a man may see, so also he may 
hear double or treble, by multiplication of echoes, 
which echoes are sounds as well as the original; and 
not being in one and the same place, cannot be inherent 
in the body that maketh them. Nothing can make any 
thing which is not in itself : the clapper hath no sound 
in it, but motion, and maketh motion in the internal 
parts of the bell; so the bell hath motion, and not 
sound, that imparteth motion to the air; and the air 
hath motion, but not sound; the air imparteth motion 
by the ear and nerve unto the brain; and the brain hath 
motion but not sound; from the brain, it reboundeth 
back into the nerves outward, and thence it becometh 
an apparition without, which we call sound. And to 
proceed to the rest of the senses, it is apparent enough, 
that the smell and taste of the same thing, are not the 



162 HUMAN NATURE. 

same to every man; and therefore are not in the thing 
smelt or tasted, but in the men. So likewise the heat 
we feel from the fire is manifestly in us, and is quite 
different from the heat which is in the fire: for our 
heat is pleasure or pain, according as it is great or 
moderate; but in the coal there is no such thing. By 
this the fourth and last proposition is proved, viz. 
that as in vision, so also in conceptions that arise from 
other senses, the subject of their inherence is not in 
the object, but in the sentient. 

10. And from hence also it follow eth, that whatso- 
ever accidents or qualities our senses make us think 
there be in the world, they be not there, but are seem- 
ing and apparitions only: the things that really are in 
the world without us, are those motions by which these 
seemings are caused. And this is the great deception 
of sense, which also is to be by sense corrected: for as 
sense telleth me, when I see directly, that the colour 
seemeth to be in the object; so also sense telleth me, 
when I see by reflection, that colour is not in the 
object. 



THE DOCTRINE OF HOBBES CONCERNING 

THE NATURE OF SPIRIT AND 

OF GOD 



SELECTIONS FROM LEVIATHAN. 
CHAPTERS XL, XII., XXXI, XXXIV. 



LEVIATHAN 
PART I. 

CHAPTER XL 

OF THE DIFFERENCE OF MANNERS. 
********* 

Curiosity, or love of the knowledge of causes, draws 
a man from the consideration of the effect, to seek 
the cause; and again, the cause of that cause; till of 
necessity he must come to this thought at last, that there 
is some cause, whereof there is no former cause, but is 
eternal; which is it men call God. So that it is im- 
possible to make any profound inquiry into natural 
causes, without being inclined thereby to believe there 
is one God eternal ; though they cannot have any idea 
of him in their mind, answerable to his nature. For as 
a man that is born blind, hearing men talk of warming 
themselves by the fire, and being brought to warm 
himself by the same, may easily conceive, and assure 
himself, there is somewhat there, which men call fire, 
and is the cause of the heat he feels; but cannot 
imagine what it is like; nor have an idea of it in his 
mind, such as they have that see it: so also by the 
visible things in this world, and their admirable order, 
a man may conceive there is a cause of them, which 
165 



166 LEVIATHAN. 

men call God; and yet not have an idea, or image 
of him in his mind. 

And they that make little, or no inquiry into the 
natural causes of things, yet from the fear that pro- 
ceeds from the ignorance itself, of what it is that 
hath the power to do them much good or harm, are 
inclined to suppose, and feign unto themselves, sev- 
eral kinds of powers invisible; and to stand in awe 
of their own imaginations; and in time of distress to 
invoke them ; as also in the time of an expected good 
success, to give them thanks ; making the creatures of 
their own fancy, their gods. By which means it hath 
come to pass, that from the innumerable variety of 
fancy, men have created in the world innumerable sorts 
of gods. And this fear of things invisible, is the 
natural seed of that, which every one in himself calleth 
religion ; and in them that worship, or fear that power 
otherwise than they do, superstition. 

And this seed of religion, having been observed 
by many; some of those that have observed it, have 
been inclined thereby to nourish, dress, and form 
it into laws; and to add to it of their own invention, 
any opinion of the causes of future events, by which 
they thought they should be best able to govern 
others, and make unto themselves the greatest use 
of their powers. 

CHAPTER XII. 

OF RELIGION. 

Seeing there are no signs, nor fruit of religion, but 
in man only; there is no cause to doubt, but that 
the seed of religion,, is also only in man; and con- 



OF RELIGION. 167 

sisteth in some peculiar quality, or at least in some 
eminent degree thereof, not to be found in any other 
living creatures. 

And first, it is peculiar to the nature of man, to be 
inquisitive into the causes of the events they see, 
some more, some less; but all men so much, as to 
be curious in the search of the causes of their own 
good and evil fortune. 

Secondly, upon the sight of anything that hath a 
beginning, to think also it had a cause, which deter- 
mined the same to begin, then when it did, rather than 
sooner or later. 

Thirdly, whereas there is no other felicity of beasts, 
but the enjoying of their quotidian food, ease, and 
lusts; as having little or no foresight of the time to 
come, for want of observation, and memory of the 
order, consequence, and dependence of the things they 
see ; man observeth how one event hath been produced 
by another ; and remembereth in them antecedence and 
consequence; and when he cannot assure himself of 
the true causes of things, (for the causes of good and 
evil fortune for the most part are invisible,) he sup- 
poses causes of them, either such as his own fancy 
suggesteth; or trusteth the authority of other men, 
such as he thinks to be his friends, and wiser than 
himself. 

The two first, make anxiety. For being assured 
that there be causes of all things that have arrived 
hitherto, or shall arrive hereafter; it is impossible 
for a man, who continually endeavoureth to secure 
himself against the evil he fears, and procure the good 
he desireth, not to be in a perpetual solicitude of the 
time to come ; so that every man, especially those that 
are over provident, are in a state like to that of Pro- 



168 LEVIATHAN. 

metheus. For as Prometheus, which interpreted, is 
the prudent man, was bound to the hill Caucasus, a 
place of large prospect, where, an eagle feeding on his 
liver, devoured in the day, as much as was repaired 
in the night : so that man, which looks too far before 
him, in the care of future time, hath his heart all the 
day long, gnawed on by fear of death, poverty, or 
other calamity; and has no repose, nor pause of his 
anxiety but in sleep. 

This perpetual fear, always accompanying mankind 
in the ignorance of causes, as it were in the dark, 
must needs have for object something. And therefore 
when there is nothing to be seen, there is nothing to 
accuse, either of their good, or evil fortune, but some 
power, or agent invisible: in which sense perhaps it 
was, that some of the old poets said, that the gods 
were at first created by human fear : which spoken of 
the gods, that is to say, of the many gods of the 
Gentiles, is very true. But the acknowledging of one 
God, eternal, infinite, and omnipotent, may more easily 
be derived from the desire men have to know the 
causes of natural bodies, and their several virtues, and 
operations ; than from the fear of what was to befall 
them in time to come. For he that from any effect 
he seeth come to pass, should reason to the next and 
immediate cause thereof, and from thence to the cause 
of that cause, and plunge himself profoundly in the 
pursuit of causes ; shall at last come to this, that there 
must be, as even the heathen philosophers confessed, 
one first mover ; that is, a first, and an eternal cause of 
all things ; which is that which men mean by the name 
of God : and all this without thought of their fortune ; 
the solicitude whereof, both inclines to fear, and hin- 
ders them from the search of the causes of other 



OF RELIGION. 169 

things; and thereby gives occasion of feigning of as 
many gods, as there be men that feign them. 

And for the matter, or substance of the invisible 
agents, so fancied; they could not by natural cogita- 
tion, fall upon any other conceit, but that it was the 
same with that of the soul of man; and that the soul 
of man, was of the same substance, with that which 
appeareth in a dream, to one that sleepeth; or in a 
looking-glass, to one that is awake; which, men not 
knowing that such apparitions are nothing else but 
creatures of the fancy, think to be real, and external 
substances; and therefore call them ghosts; as the 
Latins called them imagines, and umbra; and thought 
them spirits, that is, thin aerial bodies; and those in- 
visible agents, which they feared, to be like them ; save 
that they appear, and vanish when they please. But 
the opinion that such spirits were incorporeal, or im- 
material, could never enter into the mind of any man 
by nature; because, though men may put together 
words of contradictory signification, as spirit, and in- 
corporeal; yet they can never have the imagination of 
any thing answering to them : and therefore, men that 
by their own meditation, arrive to the acknowledgment 
of one infinite, omnipotent, and eternal God, chose 
rather to confess he is incomprehensible, and above 
their understanding, than to define his nature by spirit 
incorporeal, and then confess their definition to be 
unintelligible : or if they give him such a title, it is not 
dogmatically, with intention to make the divine nature 
understood ; but piously, to honour him with attributes, 
of significations, as remote as they can from the gross- 
ness of bodies visible. 



PART II. 
CHAPTER XXXI. 

OF THE KINGDOM OF GOD BY NATURE. 



The end of worship amongst men, is power. For 
where a man seeth another worshipped, he supposeth 
him powerful, and is the readier to obey him; which 
makes his power greater. But God has no ends : the 
worship we do him, proceeds from our duty, and is 
directed according to our capacity, by those rules of 
honour, that reason dictateth to be done by the weak 
to the more potent men, in hope of benefit, for fear 
of damage, or in thankfulness for good already re- 
ceived from them. 

That we may know what worship of God is taught 
us by the light of nature, I will begin with his attri- 
butes. Where, first, it is manifest, we ought to attrib- 
ute to him existence. For no man can have the will 
to honour that, which he thinks not to have any being. 

Secondly, that those philosophers, who said the 
world, or the soul of the world was God, spake un- 
worthily of him; and denied his existence. For by 
God, is understood the cause of the world; and to 
say the world is God, is to say there is no cause of 
it, that is, no God. 

Thirdly, to say the world was not created, but 
171 



172 LEVIATHAN. 

eternal, seeing that which is eternal has no cause, is 
to deny there is a God. 

Fourthly, that they who attributing, as they think, 
ease to God, take from him the care of mankind; 
take from him his honour: for it takes away men's 
love, and fear of him ; which is the root of honour. 

Fifthly, in those things that signify greatness, and 
power ; to say he is finite, is not to honour him : for it 
is not a sign of the will to honour God, to attribute 
to him less than we can; and finite, is less than we 
can ; because to finite, it is easy to add more. 

Therefore to attribute figure to him, is not honour; 
for all figure is finite : 

Nor to say we conceive, and imagine, or have an 
idea of him, in our mind : for whatsoever we conceive 
is finite: 

Nor to attribute to him parts, or totality; which are 
the attributes only of things finite : 

Nor to say he is in this, or that place: for whatso- 
ever is in place, is bounded, and finite: 

Nor that he is moved, or resteth: for both these at- 
tributes ascribe to him place: 

Nor that there be more Gods than one; because it 
implies them all finite : for there cannot be more than 
one infinite: 

Nor to ascribe to him, (unless metaphorically, mean- 
ing not the passion but the effect,) passions that par- 
take of grief ; as repentance, anger, mercy: or of want ; 
as appetite, hope, desire; or of any passive faculty: 
for passion, is power limited by somewhat else. 

And therefore when we ascribe to God a will, it is 
not to be understood, as that of man, for a rational 
appetite; but as the power, by which he effecteth 
every thing. 



THE KINGDOM OF GOD BY NATURE. 173 

Likewise when we attribute to him sight, and other 
acts of sense; as also knowledge, and understanding; 
which in us is nothing else, but a tumult of the mind, 
raised by external things that press the organical parts 
of man's body: for there is no such thing in God; 
and being things that depend on natural causes, cannot 
be attributed to him. 

He that will attribute to God, nothing but what is 
warranted by natural reason, must either use such 
negative attributes, as infinite, eternal, incomprehen- 
sible; or superlatives, as most high, most great, and the 
like; or indefinite, as good, just, holy, creator; and in 
such sense as if he meant not to declare what he is, 
(for that were to circumscribe him within the limits of 
our fancy,) but how much we admire him, and how 
ready we would be to obey him; which is a sign 
of humility, and of a will to honour him as much as 
we can. For there is but one name to signify our 
conception of his nature, and that is, I am : and but 
one name of his relation to us, and that is, God; in 
which is contained Father, King, and Lord. 



CHAPTER XXXIV. 

OF THE SIGNIFICATION OF SPIRIT, ANGEL, AND INSPIRA- 
TION IN THE BOOKS OF HOLY SCRIPTURE. 

Seeing the foundation of all true ratiocination, is 
the constant signification of words ; which in the doc- 
trine following, dependeth not, as in natural science, 
on the will of the writer, nor, as in common conversa- 
tion, on vulgar use, but on the sense they carry in the 



174 LEVIATHAN. 

Scripture ; it is necessary, before I proceed any further, 
to determine, out of the Bible, the meaning of such 
words, as by their ambiguity, may render what I am 
to infer upon them, obscure, or disputable. I will 
begin with the words body and spirit, which in the 
language of the Schools are termed, substances, cor- 
poreal, and incorporeal. 

The word body, in the most general acceptation, 
signifieth that which filleth, or occupieth some certain 
room, or imagined place; and dependeth not on the 
imagination, but is a real part of that we call the 
universe. For the universe, being the aggregate of all 
bodies, there is no real part thereof that is not also 
body; nor any thing properly a body, that is not also 
part of that aggregate of all bodies, the universe. 
The same also, because bodies are subject to change, 
that is to say, to variety of apparence to the sense of 
living creatures, is called substance, that is to say, 
subject to various accidents: as sometimes to be 
moved; sometimes to stand still; and to seem to our 
senses sometimes hot, sometimes cold, sometimes of 
one colour, smell, taste, or sound, sometimes of an- 
other. And this diversity of seeming, produced by 
the diversity of the operation of bodies on the organs 
of our sense, we attribute to alterations of the bodies 
that operate, and call them accidents of those bodies. 
And according to this acceptation of the word, sub- 
stance and body signify the same thing ; and therefore 
substance incorporeal are words, which when they are 
joined together, destroy one another, as if a man 
should say, an incorporeal body. 

But in the sense of common people, not all the uni- 
verse is called body, but only such parts thereof as 
they can discern by the sense of feeling, to resist their 



SPIRIT, ANGEL, AND INSPIRATION. 175 

force, or by the sense of their eyes, to hinder them 
from a farther prospect. Therefore in the common 
language of men, air, and aerial substances, use not to 
be taken for bodies, but (as often as men are sensible 
of their effects) are called wind, or breath, or (because 
the same are called in the Latin spiritus) spirits; as 
when they call that aerial substance, which in the body 
of any living creature gives it life and motion, vital 
and animal spirits. But for those idols of the brain, 
which represent bodies to us, where they are not, as in 
a looking-glass, in a dream, or to a distempered brain 
waking, they are, as the apostle saith generally of all 
idols, nothing; nothing at all, I say, there where they 
seem to be ; and in the brain itself, nothing but tumult, 
proceeding either from the action of the objects, or 
from the disorderly agitation of the organs of our 
sense. And men, that are otherwise employed, than 
to search into their causes, know not of themselves, 
what to call them; and may therefore easily be per- 
suaded, by those whose knowledge they much rev- 
erence, some to call them bodies, and think them made 
of air compacted by a power supernatural, because the 
sight judges them corporeal; and some to call them 
spirits, because the sense of touch discerneth nothing 
in the place where they appear, to resist their fingers : 
so that the proper signification of spirit in common 
speech, is either a subtle, fluid, and invisible body, or a 
ghost, or other idol or phantasm of the imagination. 
But for metaphorical significations, there be many: 
for sometimes it is taken for disposition or inclination 
of the mind; as when for the disposition to controul 
the sayings of other men, we say, a spirit of contra- 
diction; for a disposition to uncleanness, an unclean 
spirit; for perverseness, a froward spirit; for sullen- 



176 LEVIATHAN. 

ness, a dumb spirit; and for inclination to godliness 
and God's service, the Spirit of God: sometimes for 
any eminent ability or extraordinary passion, or dis- 
ease of the mind, as when great wisdom is called the 
spirit of wisdom; and madmen are said to be possessed 
with a spirit. 

Other signification of spirit I find nowhere any ; and 
where none of these can satisfy the sense of that word 
in Scripture, the place falleth not under human under- 
standing; and our faith therein consisteth not in our 
opinion ; but in our submission ; as in all places where 
God is said to be a Spirit; or whereby the Spirit of 
God, is meant God himself. For the nature of God 
is incomprehensible; that is to say, we understand 
nothing of what he is, but only that he is; and there- 
fore the attributes we give him, are not to tell one 
another, what he is, nor to signify our opinion of his 
nature, but our desire to honour him with such names 
as we conceive most honourable amongst ourselves. 

Gen. i. 2. The Spirit of God moved upon the face 
of the waters. Here if by the Spirit of God be meant 
God himself, then is motion attributed to God, and 
consequently place, which are intelligible only of 
bodies, and not of substances incorporeal; and so the 
place is above our understanding, that can conceive 
nothing moved that changes not place, or that has not 
dimension; and whatsoever has dimension, is body. 
But the meaning of those words is best understood by 
the like place, (Gen. viii. 1.) where when the earth was 
covered with waters, as in the beginning, God intend- 
ing to abate them, and again to discover the dry land, 
useth the like words, / will bring my Spirit upon the 
earth, and the waters shall be diminished: in which 
place, by Spirit is understood a wind, that is an air or 



SPIRIT, ANGEL, AND INSPIRATION. 177 

spirit moved, which might be called, as in the former 
place, the Spirit of God, because it was God's work. 



Concerning the creation of angels, there is nothing 
delivered in the Scriptures. That they are spirits, 
is often repeated: but by the name of spirit, is signi- 
fied both in Scripture, and vulgarly, both amongst 
Jews and Gentiles, sometimes thin bodies: as the air, 
the wind, the spirits vital and animal of living crea- 
tures ; and sometimes the images that rise in the fancy 
in dreams and visions ; which are not real substances, 
nor last any longer than the dream, or vision they 
appear in; which apparitions, though no real sub- 
stances, but accidents of the brain; yet when God 
raiseth them supernaturally, to signify his will, they 
are not improperly termed God's messengers, that is 
to say, his angels. 

And as the Gentiles did vulgarly conceive the im- 
agery of the brain, for things really subsistent without 
them, and not dependent on the fancy ; and out of them 
framed their opinions of demons, good and evil ; which 
because they seemed to subsist really, they called sub- 
stances; and, because they could not feel them with 
their hands, incofporeal: so also the Jews, upon the 
same ground, without any thing in the Old Testament 
that constrained them thereunto, had generally an 
opinion, except the sect of the Sadducees, that those 
apparitions, which it pleased God sometimes to pro- 
duce in the fancy of men, for his own service, and 
therefore called them his angels, were substances, not 
dependent on the fancy, but permanent creatures of 
God ; whereof those which they thought were good to 
them, they esteemed the angels of God, and those they 



178 LEVIATHAN. 

thought would hurt them, they called evil angels, or 
evil spirits ; such as was the spirit of Python, and the 
spirits of madmen, of lunatics and epileptics : for they 
esteemed such as were troubled with such diseases, 
demoniacs. 

But if we consider the places of the Old Testament 
where angels are mentioned, we shall find, that in 
most of them, there can nothing else be understood 
by the word angel, but some image raised, super- 
naturally, in the fancy, to signify the presence of God 
in the execution of some supernatural work ; and there- 
fore in the rest, where their nature is not expressed, 
it may be understood in the same manner. 



To mention all the places of the Old Testament 
where the name of angel is found, would be too long. 
Therefore to comprehend them all at once, I say, there 
is no text in that part of the Old Testament, which 
the Church of England holdeth for canonical, from 
which we can conclude, there is, or hath been created, 
any permanent thing, understood by the name of spirit 
or angel, that hath not quantity ; and that may not be 
by the understanding divided; that is to say, con- 
sidered by parts ; so as one part may be in one place, 
and the next part in the next place to it ; and, in sum, 
which is not (taking body for that, which is somewhat 
or some where,) corporeal; but in every place, the 
sense will bear the interpretation of angel, for messen- 
ger; as John Baptist is called an angel, and Christ 
the Angel of the Covenant ; and as, according to the 
same analogy, the dove and the fiery tongues, in that 
they were signs of God's special presence, might also 
be called angels. Though we find in Daniel two names 



SPIRIT, ANGEL, AND INSPIRATION. 179 

of angels, Gabriel and Michael; yet it is clear out of 
the text itself, (Dan. xii. 1) that by Michael is meant 
Christ, not as an angel, but as a prince: and that 
Gabriel, as the like apparitions made to other holy men 
in their sleep, was nothing but a supernatural phan- 
tasm, by which it seemed to Daniel, in his dream, that 
two saints being in talk, one of them said to the other, 
Gabriel, Let us make this man understand his vision: 
for God needeth not to distinguish his celestial servants 
by names, which are useful only to the short memories 
of mortals. Nor in the New Testament is there any 
place, out of which it can be proved, that angels, except 
when they are put for such men as God hath made 
the messengers and ministers of his word or works, 
are things permanent, and withal incorporeal. That 
they are permanent, may be gathered from the words 
of our Saviour himself, (Matt. xxv. 41) where he 
saith, it shall be said to the wicked in the last day, 
Go ye cursed into everlasting fire prepared for the 
Devil and his angels: which place is manifest for the 
permanence of evil angels, (unless we might think the 
name of Devil and his angels may be understood of 
the Church's adversaries and their ministers) ; but then 
it is repugnant to their immateriality; because ever- 
lasting fire is no punishment to impatible substances, 
such as are all things incorporeal. Angels therefore 
are not thence proved to be incorporeal. In like man- 
ner where St. Paul says, (1 Cor. vi. 3) Know ye not 
that we shall judge the angels ? and 2 Pet. ii. 4, For 
if God spared not the angels that sinned, but cast them 
down into hell: and (Jude i. 6) And the angels that 
kept not their first estate, but left their own habitation, 
he hath reserved in everlasting chains under darkness 
unto the judgment of the last day: though it prove the 



i8o LEVIATHAN. 

permanence of angelical nature, it confirmeth also their 
materiality. And (Matt. xxii. 30) In the resurrection 
men do neither marry nor give in marriage, but are as 
the angels of God in heaven: but in the resurrection 
men shall be permanent, and not incorporeal ; so there- 
fore also are the angels. 

There be divers other places out of which may be 
drawn the like conclusion. To men that understand 
the signification of these words, substance, and incor- 
poreal; as incorporeal is taken, not for subtle body, 
but for not body; they imply a contradiction : insomuch 
as to say, an angel or spirit is in that sense an incor- 
poreal substance, is to say in effect, there is no angel 
nor spirit at all. Considering therefore the signifi- 
cation of the word angel in the Old Testament, and 
the nature of dreams and visions that happen to men 
by the ordinary way of nature ; I was inclined to this 
opinion, that angels were nothing but supernatural 
apparitions of the fancy, raised by the special and 
extraordinary operation of God, thereby to make his 
presence and commandments known to mankind, and 
chiefly to his own people. But the many places of 
the New Testament, and our Saviour's own words, and 
in such texts, wherein is no suspicion of corruption 
of the Scripture, have extorted from my feeble reason, 
an acknowledgment and belief, that there be also angels 
substantial, and permanent. But to believe they be 
in no place, that is to say, no where, that is to say, 
nothing, as they, though indirectly, say, that will have 
them incorporeal, cannot by Scripture be evinced. 



SELECTED PASSAGES 

FROM 

ELEMENTORUM PHILOSOPHISE SECTIO 
PRIMA DE CORPORE. 



SELECTIONS FROM DE CORPORE. 

The Elements of Philosophy Concerning Body is an 
English version, by an unnamed translator, of the De Corpore 
of Hobbes. Though the translation was revised by Hobbes, 
it is none the less an unsatisfactory version — sometimes 
inexact, again so literal that it is fairly uncouth, and 
at times even positively misleading. The following selections, 
topically ordered, comprise definitions and statements of fun- 
damental importance to the system of Hobbes. It will appear 
that the Latin is both clearer and more forcible than the cor- 
responding English ; yet the English rendering of these pas- 
sages will be found to be " for substance of doctrine " correct. 



182 



I. IMAGINARY SPACE AND TIME. 
Chapter VII. (i), (2) and (3), in part. 

1. Doctrinae naturalis exordium, optime (ut supra 
ostensum est) a privatione, id est, a ficta universi sub- 
latione, capiemus. Supposita autem tali rerum annihi- 
latione, quaeret fortasse aliquis, quid reliquum esset, 
de quo homo aliquis (quern ab hoc universo rerum in- 
teritu unicum excipimus) philosophari, vel omnino 
ratiocinari, vel cui rei nomen aliquod ratiocinandi causa 
imponere posset. 

Dico igitur, remansuras illi homini, mundi et cor- 
porum omnium, quae, ante sublationem eorum, oculis 
aspexerat, vel aliis sensibus perceperat, ideas, id est 
memoriam imaginationemque magnitudinum, motuum, 
sonorum, colorum, &c. atque etiam eorum ordinis et 
partium; quae omnia etsi ideae tantum et phantasmata 
sint, ipsi imaginanti interne accidentia, nihilominus tan- 
quam externa, et a virtute animi minime dependentia, 
apparitura esse. . . . 

2. Jam si meminerimus, seu phantasma habuerimus 
alicujus rei, quae extiterat ante suppositam rerum ex- 
ternarum sublationem, nee considerare velimus, qualis 
ea res erat,* sed simpliciter quod erat extra animum, 
habemus id, quod appellamus spatium, imaginarium 
quidem, quia merum phantasma, sed tamen illud ipsum, 
quod ab omnibus sic appellatur. . . . Reversus 
itaque ad institutum, spatii definitionem hanc esse dico, 



Cf. the English version. 

183 



184 DE CORPORE. 

spatium est phaniasma rei existentis, quatenus exis- 
tentis* id est, nullo alio ejus rei accidente considerato 
prseterquam quod apparet extra imaginantem. 

3. . . . Tota ergo definitio temporis talis est, 
tempus est phantasma motus, quatenus in motu imagi- 
namur prius et posterius, sive successionem ;* quae con- 
venit cum definitione Aristotelica, tempus est numerus 
motus secundum prius et posterius et tempus est phan- 
tasma motus numerati, illud autem tempus est mensura 
motus non ita recte dicitur, nam tempus per motum, 
non autem motum per tempus, mensuramus. 

II. BODY AND ACCIDENT. 

a. Definitions. 

Chapter VIII. (1) and (2), in part. 

1. Intellecto jam quid sit spatium imaginarium, in 
quo nihil esse externum supposuimus, sed meram 
eorum, quae olim existentia imagines suas in animo re- 
liquerant, privationem; supponamus deinceps aliquid 
eorum rursus reponi, sive creari denuo; necesse ergo 
est ut creatum illud sive repositum, non modo 
occupet aliquam dicti spatii partem, sive cum ea coin- 
cidat et coextendatur, sed etiam esse aliquid, quod ab 
imaginationef nostra non dependet. Hoc autem ipsum 
est quod appellari solet, propter extensionem quidem, 
corpus; propter independentiam autem a nostra cogita- 
tionet subsist ens per se; et propterea quod extra nos 



* Cf. the English. 

f Cf. the English, and note both how loosely it conforms to the 
Latin and how it fails to distinguish these similar but differentiated 
terms. 



BODY AND ACCIDENT. 185 

subsistit, exist ens; denique quia sub spatio imaginario 
substerni et supponi videtur* ut non sensibus sed ra- 
tione tantum aliquid ibi esse intelligatur, suppositum et 
subjectum. Itaque definitio corporis hujusmodi est, 
corpus est quicquid non dependens a nostra cogitatione 
cum spatii parte aliqua coincidit vel coextenditur. 

2. Quid autem sit accidens non tarn facile defini- 
tione quam exemplis explicari potest. . . . His 
ut satisfiat, optime, . . . respondent illi qui acci- 
dens definiunt esse modum corporis, juxta quenr\ con- 
cipitur; quod est idem ac si dicerent, accidens esse 
facultatem corporis qua sui conception nobis im- 
primit. 

b. Body as occupying real space. 

Chapter VIII. (4). 

4. Extensio corporis idem est quod magnitudo ejus, 
sive id quod aliqui vocant spatium reale; magnitudo 
autem ilia non dependet a cogitatione nostra, sicut 
spatium imaginarium, hoc enim illius effectus est, mag- 
nitudo causa; hoc animi, ilia corporis extra animum 
existentis accidens est. 

III. MOTION, 
a. Definitions. 

Chapter XV. (1), first sentence. 

Proxima ordine tractatio est de motu et magnitudine, 
corporum accidentibus maxime communibus. 



*Cf. the English. 
t Cf. the English. 



186 DE CORPORE. 

Chapter VIII. (10), in part. 

Motus est continua unius loci relictio et alterius ac- 
quisitio ; locus autem, qui relinquitur, terminus a quo, 
qui acquiritur, terminus ad quern dici solet; continuam 
dico, propterea quod corpus quantulumcumque sit, non 
potest totum simul a toto loco priore ita excedere, ut 
pars ejus non sit in parte quae sit utrique loco, nimirum 
relicto et acquisito, communis. . . . 

Moveri autem aliquid nisi in tempore concipi non 
potest. Est enim tempus, ex definitione, phantasma, 
id est, conceptus motus ; itaque concipere moveri aliquid 
non in tempore esset concipere motum non concepto 
motu, quod est impossible. 

b. Cause of Motion. 

Chapter IX. (7) in part. 

Causa motus, nulla esse potest in corpore nisi con- 
tiguo et moto. Sint enim duo corpora quaelibet non 
contigua, inter quae aut spatium, quod inter jacet, vacu- 
um sit, aut si plenum, plenum tamen corpore quies- 
cente, propositorum autem corporum unum quiescere 
supponatur. Dico quieturum semper; nam si move- 
bitur ; causa ejus motus per caput 8, articulum 19, erit 
in corpore* externo ; si igitur, inter ipsum et externum 
fllud, vacuum spatium sit, possumus concipere. utcun- 
que se habeant corpora externa vel ipsum patiens 
(modo supponatur nunc quiescere), quieturum esse 
quamdiu ab iis* non contingitur; cum autem causa 
(per definitionem) sit aggregatum accidentium om- 



*Cf. the English. 



MOTION. 187 

nium quibus suppositis effectum non sequi concipi non 
potest, accidentia quae sunt vel in externis vel in ipso 
patiente, causa futuri motus non erit, similiter quia con- 
cipi potest id quod jam quiescit quieturum adhuc, eti- 
amsi ab alio corpore contingatur modo corpus illud non 
moveatur, non erit causa motus in contiguo corpore 
quiescente. Itaque causa motus in corpore nulla est, 
nisi in contiguo et moto. 

c. All Change is Motion. 

Chapter IX. (9). 

Hoc posito, necesse est ut mutatio aliud non sit prae- 
ter partium corporis mutati motum. Primo enim mu- 
tari nihil dicimus praeterquam quod sensibus nostris 
aliter apparet quam ante apparuit. Secundo, illae ap- 
parentiae sunt ambae effectus producti in sentiente; 
itaque si diversi sunt, necesse est per praecedentem, ut 
vel agentis pars aliqua ante quiescens jam moveatur, et 
sic mutatio consistit in eo motu ; vel ante mota, nunc 
aliter moveatur, et sic quoque consistit mutatio in novo 
motu, vel ante mota nunc quiescat, quod fieri nisi per 
motum non posse supra demonstravimus, et ita rursus 
mutatio motus est, vel denique aliquid horum contingit 
patienti vel parti ejus, atque ita omni modo mutatio 
consistet in motu partium ejus corporis quod sentitur, 
vel ipsius sentientis, vel utriusque. Itaque mutatio 
motus est (nimirum partium agentis vel patientis) 
quod erat propositum demonstrare. Huic autem con- 
sequens est, quietem nullius rei causam esse, neque 
omnino per earn quicquam agi, ut quae neque motus 
neque mutationis ullius causa sit. 



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